Water proofness was my secondary selection criteria right after direct HR sensor connectivity when I purchased my Polar Loop.
I don't scuba or even snorkel (since the waters here are so murky you wouldn't see anything anyway) but I paddle in a sea kayak (and flip occasionally) and would very much like telemetry of me swimming laps in the pool every weekend. Both of these activities require full water proofness to happen - water resistance would mean fried electronics.
A very Finland specific issue is also the sauna - since the water in a sauna is distributed as pressurized vapor it penetrates very well into 'water resistant' gear and we have a rule of thumb that if a watch is rated for 100ft or more its ok to take into a sauna, but anything less and you risk corroding the internals of your watch. And we have saunas 2-4 times a week so no, I'm not going to take my watch off for sauna.
I don't scuba or even snorkel (since the waters here are so murky you wouldn't see anything anyway) but I paddle in a sea kayak (and flip occasionally) and would very much like telemetry of me swimming laps in the pool every weekend. Both of these activities require full water proofness to happen - water resistance would mean fried electronics.
A very Finland specific issue is also the sauna - since the water in a sauna is distributed as pressurized vapor it penetrates very well into 'water resistant' gear and we have a rule of thumb that if a watch is rated for 100ft or more its ok to take into a sauna, but anything less and you risk corroding the internals of your watch. And we have saunas 2-4 times a week so no, I'm not going to take my watch off for sauna.