it is basically a flimsy piece of paper, God knows how that will last the coming years.
Yes it's a pain in the ass to carry around compared to the old credit card sized ID you used to get, mine is folded up in my wallet and is a bit tattered already just after a few months.
even if the police stop you, they're not going to care less about you having it or not at the moment
I've been stopped by the police a few times and they always required my polish ID.