Boating and swimming are barely related. You go boating because you don't want to swim. Kind of like pilots fly and parachutist jump. Wear a pfd and don't worry about it. Get the boat that fits what you think you want to do. I presently have 2 or 3 float tubes, 4 pontoon boats, an inflatable canoe, an 8' wooden punt, an 11' alum project and an 20' jet and I have never had to swim.
You, like all new boat owners, are under the impression that you are going to research your choice and get "your" ultimate boat but that isnt reality. Probably a tube then maybe a pontoon, because you are tired of having to pee, then you'll add an electric but can't keep batteries charged. Then you'll look at a small cartopper because the wife/girlfriend/kids/grandkids don't like being left behind and you'll "only use the motor to move from spot to spot" etc, etc. until you end up with a small armada.
At least that's how it went for me.
And, FYI, tubes have an inflatable backrest for backup flotation, pontoons have at least two bladders.