The killer feature of modern watches is the vibration alarm - you can wake up even if you use earplugs/headphones/noise machine and you won't wake up anyone else along with you. Health stuff like sleep tracking is likely useful for the vast majority of population, at least to everyone who needs time and thus lives on a schedule of some sort, without the possibility to fall asleep and wake up whenever one feels like it.

I too don't see how the ability to run apps is of any value so I use "sports" watch instead of a "smart" watch, which gives me better screen and better battery life in exchange of a smaller number of apps I won't ever run. Though the battery life is not an issue and smartwatch users I know charge their watch while in the shower.