If you leave a bronze seacock un-worked and un-lubed, they'll freeze up a lot worse.

I'll admit that we rarely exercise some of our Maralon fittings, and they've been fine.

The one concern I'd have with them is in areas where you might be mechanically abusing them (like using them as a handhold while working in a compartment. Otherwise, I think there amazingly good.

We have some bronze Groco thru-hulls which are more hard to keep free-working. If they get locked open, they're no bargain to move with just a wrist action :^))).