It was common to have a dedicated set in the aircraft as well-but this was generally onshore, witb occasional offshore flying...
It is a totally different story when the vests have to be worn frequently....
Ask yourself:
Would you be happy to wear the helmet of a pilot just getting out of the cockpit?
If yes-you are a weird guy with probably some weird sexual fetish...
If not-why should this not apply to vests as well? Or gloves? Or shoes for the matter?
A life jacket is what-100 USD?
And they are probably there already....and like helmets and other equipment, needs servicing anyway....
No, i would refuse to wear them when sweaty...like said before:
If the flight is then delayed..it becomes a problem of the company....