A watch that needs to be charged once in a few days is actually worse than one that could use a charge every night.

Charge at night is a habit that can easily be adjusted to our daily schedule. btw Apple watch does last a full day (I meant 16+ hrs) with decent use, unless you are playing music out of it all the time or obsessively checking time/calendar.

Only advantage of fitbit is that some models are easier to wear to sleep, particularly if you don't need to charge at night. However, even here, apple one is way ahead - the theater mode will make sure the super bright led at the bottom won't wake you up.