My main use of OTG was flash drives. Even 32 Gb fills up quick if you had music, movies, and other documents on it (like my n800 does).

Though the n900 has a good camera I imagine I'll still take my Canon when I go places where I know I will be taking photos. But my Canon only supports up to 4 GB. So I would take my n800+camera+a big USB drive and use the n800 to move photos over on vacations.

Granted if it can be done via bluetooth then that's ok. The only other time I have used OTG USB is when my friend and I found a random USB drive on the ground and wanted to see if we could return it if there was a name on a file.