Yes this has several benefits:
- some users prefer not to reveal their IP to your server
- some users prefer not to be tracked by their internet provider (or by Google via DNS on Android, or by local wifi users or by who knows who)
- your onion site is censorship resistant (some users in Russia or else might need it)
- your onion can be ddos-resistent (if you enable POW)
- your clearnet site might be unavailable for other reasons (unrenewed DNS entry or expired certificate)