There is a lot in this thread ....
I have been wearing a non-inflatable foam waistcoat type buoyancy aid for 30 years. I'm still here!
Why bother with inflatable? Advantage: compactness, but problem with exit means inflatables are not (in my opinion) suitable for tubing, and never were.
Disadvantage water and damp creep will set off auto inflatables with boring regularity while in the back of the car on the way home!
Disadvantage with foam sleeve-less jacket type I wear? Too warm in strong sunshine, not good in summer.
Need for a wader belt? Why make your chesties harder to put on and take off? There is no safety advantage. But if you have one, and trip in the shallows, you might take in less water with a belt in the seconds it takes you to get up again!
Bigger lifejackets always? No not always better. Sometime it may happen to be a problem
not being able to get underwater to fix something! Adequate buoyancy is adequate.
Exiting the tube? Most of the time not necessary, as it will keep you afloat, while you figure out what to do next.
Exiting? The one time you get face down in water with the tube inverted, it will be resting on the back of your body holding you in a position where your face is awash/semi submerged, and not a good place to be. Doing a doggy paddle with your hands will lift your face. Turning to the side will roll it until you are face up, but will everyone do that in that situation, or will those few panic?
How to flip one? Get in a vee tube and note where there is no buoyancy - right in front of your seated position! Get high, lean forward, and sort of hoike it over, no problem. In a very big wave the water tilts you this way every time the tube rises to the crest of the next wave. Now it is down to your boatmanship, but it was always about boatmanship, wasn't it?
Some people have
no ability to manage any small craft whether it be dinghy or tube. I took a friend out once. He opened my eyes! He fishes from huge lake boats and I found out why. He sat high, tilted, lifting the tube out on one side and pushing it down the other. Like a floating Leaning tower of Pisa. He then lost a fin in the first 15 seconds. I saw the writing on the wall and suggested we bankfish instead!