I mean, I’m not sure this actually susses out, though? At least not any more. That might’ve been the way that it was originally intended back when 3.0 was first released, but it’s definitely not the way that it’s manifested in the current economy literally anywhere that I’m aware of, and I’m not sure it’ll ever actually get there again thanks to recent changes and player inertia.
To explain, buy lists are, at least to me, intended to be highly profitable exchanges (by which I mean you are getting more value than you are putting in every time you do one of the purchases; they are not simply “break even” 1:1 conversion of currency value to something else; if this is up for debate, I’m more than willing to engage in that, as well). In the new TC buy lists, you get to purchase Basic Scrap at 2 per 1 currency. Assuming a general 50% value discount (e.g. you’re spending half as much as the value that you’re getting), 1 Basic Scrap seems to be intended to be worth roughly 1 local currency.
I understand that “local chapter economy will determine which gets more use”, but because there is a quite literal, rule driven way to directly convert money into basic scrap (and 2 step process to convert mind into herb via Basic Agriculture into uncommon/rare scrap via TC), I’d venture to say that the Scrap is, based on the default player-controlled ways to access resources, worth equal-to- or more-than- local currency (the most common mind-to-currency conversion rate I’m familiar with is 3 currency to 5 mind; I’ve also seen 1:1, but much less often; as stated before, Basic Scrap is worth roughly 1 based on the TC buy lists while TC skill usage would indicate that Uncommon and Rare, which are, imo, equally accessible since they just require Basic and Proficient, intended to be worth at least 3 currency each).
This is where you get into the generally ridiculous prices for many of the single-use crafted gizmos (like the GG Locksmithing Tools). Without even getting into the cost of the materials themselves, simply having to spend mind to get the item crafted (once again, most common conversion rate I’ve seen is 3 currency to 5 mind) makes it significantly more expensive than the buy list purchases (and the lock poppers are also better since they reduce the time to 5 secs rather than 30). If all you were doing was paying the mind cost to create the tools, you’d be paying 3, 9, and 18 currency, respectively (which fits in line with the general “50% value discount” that the buy lists seem to espouse; 2/10/20 would be the “perfect” point). However, the resource costs make that significantly more (Conductive Metal costs 5 mind but, since Trailblazing is a once-per-event rather than at-will resource gain, it gets a scarcity mark-up to roughly 6 currency; Basic, Uncommon, and Rare Scrap are priced at 1/3/3, as previously calculated), with final prices for Basic Locksmithing Tools at 11 currency (3+6+2x1), Proficient at 23 (9+6+2x1+2x3), and Master at 38 (18+6+2x1+2x3+2x3).
So you end up paying 11 times as much for the Basic Locksmithing Tools as the Basic Lockpopper, 4.6 times as much for the Proficient, and 3.8 times as much for the Master. For an item that is, explicitly, worse (30 seconds rather than 5 seconds). The only benefit that the Locksmithing Tools have is the PFA ability (which is, ironically, for the Stealth PFA rather than the Larcency PFA; according to the database, the Locksmithing Tools require Stealth to use in general and Larceny to use at each level; since the Lockpoppers require Crim and Larceny, the Locksmithing Tools aren’t even “easier” to use in the sense that they only require one skill since you still need a combination of two skills to use them).
This moves into one of the general gripes I have about the blueprints for single-use items (traps are included in this): because they follow the same resource consumption paradigm as reusable items, they are profoundly expensive, which means that very few people ever use them (especially given how you can often accomplish the same effect just as easily and for significantly cheaper by using a buy list item; the buy list item is often priced appropriately for the benefit of the effect, but the crafted items, thanks to the crafting requirements that seem selected more for verisimilitude than game mechanics, are prohibitively expensive). A similar example of this occurs with the Moulen Rouse Camouflage (at the Proficient level, you’re spending ~35-45 mind, 15 mind to craft, 10 mind for Plastics, and 5 mind each for the Uncommon Herb; Basic Herb is 0-5 mind depending on whether you’re Foraging or Agriculture; and all it does saves 9 mind, since you’re spending 1 mind to get an hour of disguise, which would normally cost you 5 mind twice).
In general (I would venture to say “universally”, even), the single-use non-healing/recovery items (gizmos, traps, poisons; I did a whole thing on the economics of poison about year ago and, while they’ve gotten better, I doubt they’re anywhere near what people would consider “cost-effective”, especially compared to the Crim Inf options) would benefit significantly from being reduced to a single level. You don’t need 3 levels of traps or 3 levels of locksmithing tools; it just ends up needlessly complicating things and the need for compounding construction costs and materials just makes them too expensive to bother crafting or using. Conversely, don’t add any additional materials to the construction cost or reduce the mind cost and time costs to increase it to proficient or master (or follow a similar paradigm as Culinary, which is all one-use items anyways). Or, you know, give it more than one use (I can 100% see a disguise kit getting 5+ uses, and while it makes some sense that a Lock Popper is consumed upon use, since I imagine it being some kind of chemical charge, I find it strange that artisanal Locksmithing Tools aren’t robust enough to last more than 1 use).
Unless you’re using an extremely high valuation of currency or precipitously low value of scrap and herb that doesn’t match any economy that I’m familiar with, the costs of constructing the single-use gizmos is prohibitively expensive, even when you factor in how cost-effective buy list purchases are supposed to be. They need to be made cheaper, have more uses, and/or have a single level of crafting with multiple levels of usage.