Its mainly a convenience feature. If you associate a particular key with a profile, the car will customize a bit to that profile: welcome message (Hello <your name>), show customized picture (if desired), use your preferred navigation settings (voice prompt, home location, routing preferences, etc), use your preferred music selection (radio, USB, etc), load your preferred HUD/binnacle layout, things like that.
So nothing critical, but all stuff that I took for granted on my Tesla.
It should load your seat memory too, but my Ariya has stopped doing that. May be a bug. They copied that from Tesla, too.
Forgot to answer your question about how to set it: in the Nissan Connect screen, tap: Home icon -> Gear icon -> Edit User -> User Profiles.
So nothing critical, but all stuff that I took for granted on my Tesla.
It should load your seat memory too, but my Ariya has stopped doing that. May be a bug. They copied that from Tesla, too.
Forgot to answer your question about how to set it: in the Nissan Connect screen, tap: Home icon -> Gear icon -> Edit User -> User Profiles.