>>16427961Really, any team that needs a momentum builder that can take a hit and can afford to use up a slot for a grass type.
His grass typing is a blessing, many times you'll know someone is going for the leech seed and you get a free switch in. His ability to use Will-O-Wisp means that frees up a status effect for your team, giving you more utility against scary physical attackers, or a way to help widdle down seemingly impassable walls.
Most of the time, it's going to be fairly obvious when Rotom C is going to be hit for a super effective move, and that's when you either Volt Switch out or hard switch, depending on how fast you think your opponent is.
He's not the best grass type, but his typing and ability certainly make him a unique character.
Also, it should be noted, that all the Rotoms are also immune to sticky web, which is a nice bonus.