No, you don't understand what resistant and proof mean. Waterproof means that is can stay in water indefinitely and at any depth, water resistant means it will remain waterproof for a certain amount of time at a certain pressure (depth). The IP68 rating on phones is water resistance, not truly waterproof. The designation just confuses people who don't bother reading because they title it inaccurately. There's many forums online that explain this.
Please show me where Samsung said that consumers can use the phone underwater and while swimming?
EDIT: I'll help, look at moisture protection 8 (
http://www.cnet.com/how-to/water-dust-resistance-ratings-in-gadgets-explained/) it is for accidental submersion and splashing. It is not waterproof and meant to be used underwater. It's accident protection, not an actual usage feature. The whole idea of "waterproof" is marketing, not fact. Anyone who reads up about IP68 knows this.
A device needs to be 50M water resistant before you ever swim with it. The IP68 isn't even close.