I have a Garmin Descent Mk2i which I use for scuba diving, and it's a fabulous all-purpose fitness and adventure watch. I've used to for hundreds of dives, navigation on multiple backpacking trips, cycling, and tons of other stuff. I even wear it daily, and it nicely supports notifications from my phone.

When Garmin originally launched a scuba watch, I was kind of surprised. It's a small market, and there were a lot of established "good enough" players in the space. Everyone already had a dive computer. Who would want an expensive one from Garmin when they could buy an expensive one from Shearwater? But Garmin showed up with a good product, iterated by adding their sonar based SubWave for air integration, and eventually took a lot of marketshare by including fitness and smartwatch features the competitors lacked. Now I see tons of Garmins on dive boats. People love them.