Even with rockets, you can test with unmanned launches. You don't really get "practice rounds" like that with brain surgery.

because people won’t die if you get the quantum physics wrong.

Well, not with that attitude!

(Okay, I guess, in pure quantum physics, nobody is going to get hurt by it. But if you venture into applied quantum physics -- quantum engineering -- then you begin to reintroduce the possibility that getting it wrong could cause serious harm in some cases.)