Methinks you underestimate the complexity.

Maybe I do. But there are dozens of Chinese no-name companies who developed entire smartwatch ecosystems.

Yeah, I feel you. There was a time, some ten years ago, when computers / the web / tech in general were actually great and not those emshittyfied things we have to use now. There are too much people that are just compliant enough to use every shit that gets shoved down their throat, to the loint that it os damn hard to boycott all the shitty thing and not be effectively Amish.

I never had one (but did want one, just financially couldn't justify it at the time), but it would have a great fit for me. I just wanted a watch to tell the time, and display my phone notifications plus vibrate to alert me to them. That would have been legitimately useful for the job I was in at the time which was challenging to carry a phone (but it was nearby in my bag).

Now, I have no use for any of that. But I am now interested in a heart rate monitor that doesn't hoover my data to replace my old dedicated Polar heart rate monitor (which also told the time, but I only wore it exercising), so the more expensive model is tempting!