Apple also advertises their watches as water resistant and shows ads with people swimming. But as soon as you get some water ingress, you are SOL since it is not guaranteed.
And it does work, I would have over 150 recorded swimming workouts (45 minutes to an hour each) on my Apple Watch SE.
What do I mean? In hardware manufacturing lines, if you guarantee water immersion, you actually do that test as part of manufacturing, either using real water or something known as "dryleak" where you gauge air displacement in a fitted and known volume fixture.
Apple and most phone manufacturers aren't going bother with that test since it's extra labor and time, so they instead live with never warranting it.
It doesn't take much to have a water ingress issue. Even a tiny tiny defect in the adhesive gasket gluing the phone together can lead to ingress.
They'll argue (maybe rightfully so) that a water resistance rating is not the same as the pressures of swimming. Just dunking something does not do anything such as swimming strokes that could force water into the watch. I find it a little absurd that people won't wash dishes with a 100m resistant watch, but then again, I'm not sporting a 5 figure watch either.
Many threads with complaints that people are using their Apple Watches as intended and as marketed, but once there is a bit of water ingress, Apple will not cover the damage (outside of normal warranty period).
*but we don't recommend you use it beyond 40m and may degrade over time.
Worse than that. It was tested and as soon as you pass 40m, it gives a warning, stops displaying the depth and just tells you ASCEND. Once you are above 40m it functions again but the No Decompression Limit is no longer reliable, as it doesn't track the actual depth you were at, while >40m.
Anyone going deeper would be doing tech diving and would need to be using a proper dive computer.