I cannot speak for all parts of the world, but from the beaches I know, Florida, this is never the advice they give - I’d bet this is dead wrong. A riptide current does not care if you are in the shallow or not. Having a floatation device not only helps you stay afloat, it helps you get noticed. Always bring a floaty.
“It may deflate” - I can’t swim for an hour, but I’d bet any shitty floaty will stay afloat for an hour.
“Sacred cows” got a chortle out of me