Precisely, its an individuals choice.
For me, I prefer to swim unhindered until I choose inflation of the jacket. I want the ability to swim without restriction, and to be able to climb onto things, upturned boats, rafts, etc, or out of the water in some way without the life jacket in the way: until that point in time that additional flotation becomes necessary for me. Life Jackets of all types are a hinderance in that respect, but you need personal flotation to be instantly available for when you need it. For me thats my choice, but I respect all choices that others make.
There are a lot of right ways to comply with your legal and moral obligations.
Cheers
Mick