I have the inflatable belt type for my dragon boat racing. I've only ever been over once in a dragon boat. But I use the full vest for my SUP and OC-1. Those are a lot easier to get off/out of. And if as you fall you hit your head, chances are that you vest will get you upright. With the inflatables you have the where with all to pull the cord. If you're out for a few seconds, that might not happen. Now there are inflatable vests that will inflate when they get wet. I always thought the CCG had decreed we needed that type of pfd for the SUP, but could not find the regulation.
And if your water is a little cool, the vest will keep you warmer.
And if your water is a little cool, the vest will keep you warmer.