Baton Pass can be useful as it allows you to pass increases/decreases in stats. Pokemon like Ninjask is notorious for Swords Dancing then Baton Passing to a Pokemon that could do with an increase in ATK and Speed (It has Speed Boost).
There are whole teams based on Baton Pass (which are rare). The idea is to string together as many boosts as possible meaning most if not all team members should have baton pass. If you switch your Pokemon, the boosts do not pass on. You can baton pass until your Pokemon are pretty much invincible with defense and special defense raising moves.
Baton Pass also can be used like U-Turn for momentum. If you know your opponent will be switching, Baton Pass. This allows you the freedom of choosing which Pokemon to switch in after your opponent has made the switch. This guarantees you the advantage whereas hard switching means you need to guess what Pokemon is coming in.
