My understanding is that they are not chemically the same: you can't smoke cocaine or amphetamine salts; they'll burn instead of vaporizing. You need to first swap what stabilizer the active component is bound to. i.e. perform some reaction to convert to crack/meth. The point of doing that conversion is to be able to smoke it. My understanding is it's also not just fast acting, but quite a bit more intense. So e.g. more likely to trigger psychosis instead of just making you talk a lot, clean the house, get good grades, etc.

Hmmm, I’ll admit I did a cursory amount of research and tried a source that looked as unbiased as I could manage without diving super deeply.

I have smoked cocaine before (on a blunt with cannabis) and it felt like I felt something but who knows.