I've worked on a few benches covered with galvanized.
The worst that might happen is it'll turn white if moisture sits on it for any length of time... but it's a work bench, doubt that'll be a huge issue (the turning white part).
Our shop has a small bench covered with 20 ga galvanized, there's a few dings and dents in it, but the base isn't all that great to begin with. It's got some staining and some random discolored spots, but it's good enough for a bench.
My favorite thing about metal top benches, you can write on them with a marker, and it mostly stays until you wipe it off with a cleaner of some kind.