I see no purpose of online check in and don’t bother. Once I tried when the front desk check in line was long, but that was due to housekeeping backlog causing rooms to not be ready and it didn’t help.

I remember working at Starwood years back when they introduced this feature - the percentage of people using it was really low, begging the question of whether it was worth it. Not only does it require the IT work of the central systems, but also upgrades to door locks of all rooms of each property (if the phone is to open the door and truly bypass front desk).