No, charge every night would be way worse. My wife uses her Fitbit to track her sleep, and it does this very well (much better than her previous smartwatch). She also tracks how much she walks during the day. A smartwatch that has to be charged every day would be useless to her.
I have no idea about the UI that some people complain about, but my wife seems to have managed to get access quite a bit of functionality in her Fitbit, so I'd say it's good enough for its purpose.
I recommend using a separate sleep tracker. I was using the Fitbit constantly and got some skin irritation when I forgot to swap wrists before bed. Though, I was using a narrow version which probably made things worse.
FWIW my Apple Watch S4 can go a whole weekend on a single charge. I don't use mine extensively, though I do use Apple Pay for every transaction that I can. You can def go 2-2.5 days on a single charge.
That's right, a watch that does literally nothing but tell the time lasts a long time on a single battery charge. If having to charge your watch is not worth the benefits/luxuries provided by an expensive smartwatch, a smartwatch might not be for you.
To give a quick summary: I look at the upcoming weather, see the times of upcoming meetings, see messages people have sent me, pause/resume/skip tracks on currently-playing music, track hikes or walks, record audio, check my heart rate, check the current time/date, and pay for stuff.
Wearing a watch during sleep is annoying and can actually lead to health issues. Get a proper sleep tracker (e.g. Withings) for this. Charging nightly is perfect for a watch, really is a pro for the Apple Watch.
I have no idea about the UI that some people complain about, but my wife seems to have managed to get access quite a bit of functionality in her Fitbit, so I'd say it's good enough for its purpose.