Well even with just one person committing, you'd still have a remote. Even for personal stuff that you don't want to publish, you can still use BitBucket private repos (or bare repos on any server you have access to).

To be honest, backups wasn't what was first in my mind when answering that question (backups are a separate system in my mind), it was that being able to "git diff" to the last time it was working is often all you need to do to get your head round why it's not working now.