JB, having floats and lifejackets is not about eliminating accidents but reducing the risk of death or injury to persons.
I should add that, further to my post #14, there was a time in the past when I did a lot of harbour scenic flights in a helicopter. Not only did it have pop-out floats, we insisted on everyone wearing the type of lifevest which would only inflate if commanded, rather than the marine variety which automatically deployed when in contact with water. The obvious reason is because an inflated lifejacket may hamper emergency egress from a submerged helicopter.
That said, passengers don't go through HUET training, do they ? Nor do they wear a helmet like I do - the head is probably the least protected part of the body in such circumstances.