If you've never done squats/cleans in a shoe with a proper heel you should really try it and see the huge difference.

I think what's relevant here are your terminal goals. If they involve lifting heavy barbells in a gym then yes, specialized shoes could help. But if the terminal goals are all in the regular, out-of-gym life (e.g. be able to manhandle heavy things which need to be manhandled) then you don't want to depend on shoes which you never wear in normal life.

While I am not an unconditional supporter of Crossfit, they have a concept I like a lot -- that of nonspecific fitness, the ability to do whatever needs to be done. And outside of gym heavy things to be moved or lifted very rarely look like a barbell and it's not often that all you have to do is straighten up with them on your back.

Good form is really important, yes, but your ability to perform a movement properly shouldn't depend on what you are wearing.