Really only a handful of things:

1. navigation while traveling - don’t need it much, if at all at home, but I travel often enough for work that losing that capability would be painful.

2. MFA - authenticator apps are the most convenient way to do MFA. SMS/email are terrible options for this and should only be used if there is absolutely no other option.

3. Access to the internet while away from home, both while traveling and while out and about

4. Music playback in the car

5. Communication - most of my friends don’t use SMS/voice to talk, instead preferring Discord or Signal

Basically everything else I do on my phone could be done from a more proper computer with minimal inconvenience.