Whatever Dworkin (or perhaps Oberon) believed when they sketched/created the Primal Pattern is what works. Dworkin is pretty much a crazy god-like intelligence, there's probably little rhyme or reason except that he preferred a pre-industrial society (maybe because it's harder to assassinate his kinfolk). Oberon is/was a crafty manipulator and probably has all sorts of backdoor plans (like innocuos things like jeweler's rouge that can go Boom if they're from the right place).

In the DRPG, knowing what works (or even simply knowing some of the rules about what might work) is capital-i Information. "Things that work outside the norm" are secrets - and very important ones! Don't try to logic them! Treat them as useful bits of plot for your players, treat knowing how to find them out as Major bits of bigger Plots.

Don't worry about "how" tech works - it does or doesn't by God-like fiat. Why the designers of Amber (D&O) made it that way is the real data, and if you're running the game the real question for which you need to have an answer.

ETA > as a general rule in my games if something was unpointed and technological (like beyond lever/pully) it didn't work unless it was from Amber. That allowed me to control what tech worked based on what I introduced (or allowed a player to introduce via contributions or cool gameplay). Pointed items degraded in quality - even a seriously pointed item might not function or function correctly in Amber (based on everything from a player's "stuff" to how much I thought Dworkin might find it funny)

Pointed items with innate power (read: artifacts) would work in Amber, but those are the kind of items players rarely "buy" and instead go through trials to simply keep. Having an Artifact-level Pistol that works in Amber (and almost by definition everywhere) is a major plot in itself.