This is a really hard question, because I don't want to bring summoning most of the time in AOE crews. If I suspect an opponent to bring heavy AOE (I never try to base my crew selection on what my opponent has played before) such as my opponent chose Guild and Turf War is the strategy, I would assume they would bring Sonnia to easily clear the middle part of the board.
In these cases, I will usually select Shooting Dreamer. You can't kill Dreamer if he is always on the board. Summon a Daydream, Empty Night, Shoot things. Go nuts shooting when getting close to the big fight and switch into LCB.
I would consider taking Summoner Dreamer when possibly up against AOE when the Schemes support it. If it's Turf War but the Schemes are Power Ritual/Plant Evidence/etc or any scheme that can be completed with a few minions, I will summon Insidious Madnesses and spread them out. If they spend a model targetting one of these madnesses, then mission completed. I'm trying to do it later.
As a general suggestion; think of Chompy as a shield. He is there, the enemy is going to have take that down (unless it's Tara who just burns the kid underground) to get at Dreamer. They need to waste cards getting through Terrifying and not get utterly wasted by insta-kill triggers.
Chompy is a great Swamp. 3" claws on a 50mm base is a giant blob on the board. For Turf War, his melee range can take up a good part of the area which means they need to burn more cards for terrifying. Especially if Widow is dropping webs and daydreams are hanging around.