There are lots of videos on many flagships ; not only waterproof, shatter resistance, scratch resistance has been evaluated..It survives 1 hour under water
I think These are all methods of subtle advertising to influence our buying decisions.
The fact that, Apple isn't ready to honour claims due to water damage by not explicitly stating it's waterproof capabilities speaks a lot about it. Why would a manufacturer won't claim it's capabilities if it's genuinely waterproof. That means even Apple isn't sure of it. Probably iPhone 7 might be waterproof, 6s is thus WIP.