The logging works ok while off bluetooth...but be aware that _any_ changes are basically impossible in that state. Even basic watch functionality like changing the time or setting an alarm require a bluetooth link, the software, and an internet connection back to the fitbit servers.

Well, that's a conpletely pointless limitation. Nothing of good was lost...

I've done that occasionally, over a weekend when I left my phone at home or something. Doesn't happen often, obviously, but it does have some small number of days of local logging.