I'm not entirely sure. I'm pretty sure you don't get any daily sats, if you don't check in, but it seemed like I got credit for my steps in a challenge when I forgot to check-in one day.
You need to log in daily to sync all the steps. I have walked over 10k some days but not synced the app, as there weren't any challenge ongoing, and the steps did not count.
I'm not entirely sure. I'm pretty sure you don't get any daily sats, if you don't check in, but it seemed like I got credit for my steps in a challenge when I forgot to check-in one day.
I recommend checking in daily.