First, you and your crew have to get into it. You may be tied-up with other things.

Secondly, in rough weather in the water, you're going to get douched pretty good.

You're really depending on SAR getting to you before the elements or sharks do.

I think immersion suits are something that you wear when you're working in storm conditions in cold water. If you get washed overboard while doing your job. I doubt you're going to be wearing it in the Bahamas while on deck. They are no bargain moving about in.

Don't get me wrong, in the right circumstances, those suites are lifesavers but I think not for most cruisers. If you were singlehanding in cold waters. Going up and down a companionway, using a toilet, or trying to sit at nav station you are like the Michlein Man ;^))). If you're on a fishing boat in Alaska, and get washed overboard, your chances go up a lot. Some (of the few) fishermen that I've asked about this have suggested that while they think they are fine idea, they feel that they would be more vulnerable to being washed overboard because they hinder their ability to grab things, move around, and have a sense for what's coming.

Given everything else I've seen about your boat, I can't see you buying a used raft :^)))).