Using the Integrated Toolset as a point of comparison…
At 10 Int, 6 Electronics, 3 First Aid and 3 Mechanics you’re no longer risking a bad install for any of the CBMs. (A mutation, maybe, for the toolset itself. But that’s relatively easy to fix, for a starting character - using a purifier won’t cost you anything at that point, and they show up in chem basements.)
Even if you’re not abusing stims for extra Int.
If you started with 13 Int, you can lower electronics to 3 - again, before abusing stims.
Eating a fourpack of s’mores gets you 3 Int from stims and probably one from morale, nevermind anything addictive like, say, caffeine pills.
You can reach 3 in each of those skills with very common books.
That’s a little harder than the makeshift welder, and arguably lower than the welding rig - which requires a 2nd tier book.
Most significant cost, then, is actually finding the CBMs - and “a battery, a power source, and a toolset or three” isn’t horribly rare.
Personally, I’d be in favor of making them harder to install - at least, from the infrastructure end. Getting the skills needed for the higher-end ones can be rather more tricky.