[sshine]

Self-hostable is a good quality to reach offline first.

And open source is a good quality in general.

But software doesn't need to be self-hostable or open source to be offline first.

Being capable of running offline is the most premium feature you can give me.

For example, you can have an app on your phone that is closed source and costs money, but you can still access it without internet.

An example of an "offline first" feature that does not depend on open source or self-hosting is: Can you sync your password database to another device without internet? (A more interesting one you can't even take for granted nowadays: Can the program open if you're offline?)