As a dedicated cleric, Lanturn is definitely not a great choice. Oddly enough, in my use of him, I've rarely used Heal Bell. When I have though, it has been a great benefit to the team. I find that I'm using him more to gain tempo with Volt Switch. Volt Absorb makes him a great wall for a surprisingly large number of pokemon. Because he's so uncommon, people might not even realize how much Lanturn screws them over and so they stay in while I paralyze or Scald them. That VoltTurn combo that has started showing up with Mega Manectric and Landorus? Both of them really hate taking a scald. I've seen where Thundurus after a Nasty Plot still has nothing to hit Lanturn.
So other than Volt Absorb, why run Lanturn over Rotom-W? Well Lanturn (other than that awful ground weakness), can take more special hits than Rotom-W and pairs exceptionally well with a flyer.
So other than Volt Absorb, why run Lanturn over Rotom-W? Well Lanturn (other than that awful ground weakness), can take more special hits than Rotom-W and pairs exceptionally well with a flyer.