This is exactly my point. Without knowing how common {wearing helmets in cars, wearing PFDs in kayaks} is, the statements imply nothing about safety benefits of either, and yet that one was presented in a way that suggests that it does.

What would be a non-misleading value to quote would be absolute change of risk of drowning (e.g. that a typical trip without a PFD costs X micromorts, while a typical trip with one Y micromorts). What would be less problematic (but still potentially misleading[1]) would be a relative risk reduction (wearing PFD makes you X times less likely to die).

[1] Because it doesn't tell you anything about the original risk that you're lowering. E.g. helmets are a good protection against falling bricks: equally good at construction sites as when you're walking down the street. The only difference is that falling bricks are more likely on a construction site.