Can you seawatch with a bridge camera?
I'd say this depends on how good your seawatch viewpoint is. The locations where I seawatch are at least 100 meters from the shore, so it's very very hard for any camera to capture anything at all when seawatching conditions are best (North-western wind, high waves). I can barely take an ID picture of most shearwaters that are way too often further out at sea. You can be lucky with the occasional skua closeby though.
Seawatching itself is hard enough through telescopes (to find a bird or pick up a bird someone calls out), so I would think that trying to seawatch with a camera is a disaster.
It could be very good though if you are on a high rock with seabirds passing beneath you.