As an Apple Watch user: I've found I don't care.
That's something a lot of people use as an example, but in practice I don't find it to be a problem at all. I only had to charge my FitBit every week or two, but I don't mind what I do with my watch at all.
I plug my phone in every night, and I put my watch on its charger at the same time. That takes care of it, no need to think about it any further. The first generation Apple Watch would usually have 40 to 50% battery left when I put it on its charger at the end of the day. I'm not sure about the newer one, but I know the battery life is supposed to be better.
The FitBit could go for 10 days, but I would have to monitor it (usually wait for the app to tell me) and then go find the charger and plug it in. Oddly the fact that I charge my watch every night seems like less of a cognitive burden to me because I don't actually have to think about it. I did occasionally have to think about my FitBit.
So in practice, it's never been an issue. Because the battery is so small (due to the size of the device) even if you do run it down it charges up very fast. I know some people use them all day and sleep track with them, and then simply charge them up while taking a shower in the morning.
If you want to spend all day doing a triathlon and having GPS tracking then maybe the Apple Watch is battery wouldn't be good enough for a single day. I imagine that some company sells a gadget that would be able to handle that. The Apple Watch is battery is WAY bigger than my needs, and I imagine it sized for a lot of people. Health is turned out to be one of the biggest uses of the Apple Watch.
I think this is something like range anxiety and cars. It certainly affect some people, but for your average user and even your average user who likes to stay fit and exercise a fair bit I don't think it's an issue. It's only the most demanding and serious 5 to 10% of the market that may not be able to use an Apple Watch.
The only place I ever saw a benefit to the battery life with my FitBit was when traveling: since I don't tend to take very long trips I almost always could get by without bringing the charger. I have to bring my Apple Watch charger. Since I don't travel much, that doesn't matter much to me.