I can get another hw key (if one of mine breaks, which I, surprisingly enough, have not yet managed to achieve)

And since I have at least two at all times, the possibility of one of them breaking changes… not much really.

Paper can burn or get tossed, backups files can go corrupt, and I really don't understand what is that extra risk hw keys introduce…

There is at least one valid (in my opinion) reason to not like hw keys though: they cost real money to acquire, so you probably want an extra margin in your budget for the unlikely case they indeed decide to break.