Nope, marketing checkbox feature only (a.k.a "big fat honking lie" IMNSHO), no actual resistance whatsoever in my experience. Samsung S5 billed as "IP67 certified", meaning water resistant up to 30min/3 feet IIRC, yet denied warranty repair from 10 sec/1 inch of water, even though I had the plug in and everything. Apparently it's only resistant against dry water or something. /s

Edit: sorry for offending the downvoter - I actually like that phone, yet there I was with a wet brick.

My prior flip-phone (not a smartphone) wasn't just water-resistant, but actually waterproof and had a removable battery. You had to use a quarter to pop open the rubber seal to replace it.

I bring my IP68 Sony XZs (with minijack) into my bathtub regularly. I wouldn't recommend it though due to warranties etc, who knows what they will say.