Of course, if people at public skates keep throwing trash on the ice (candy wrappers, foil things etc) THAT kind of stuff can ruin your blades really fast. And then there are the other things that happen regardless....like clipping your other blade and getting a nick (especially if you skate synchro), popping on a hairpin/bobby pin (did that, it was an ugly fall), or a fuzz ball from a sweater (I'm guessing it was a sweater). No damage to the blade, just my pride.
I wouldn't recommend skating on a synthetic rink unless you have rental skates or really cr*ppy old skates that you don't care about. Cause they will get dull and worn. But yes, they do build up your muscles in a serious way. BUT the mechanics of the movement-very different animal and going back to the real thing is an adjustment!