In which situation should I use the Floatee anti-drowning T-shirt for children?

What's the difference between the children's anti-drowning T-Shirt, usual swimming aids (armbands, swimming rings, floating board belts, swimming vests,...) and life jackets?

Floatee, the anti-drowning T-shirt - comparison with armbands and lifejacket
Floatee, the anti-drowning T-shirt - comparison with armbands and lifejacket