>>51159318Thick Fat IS good, but how good it is will always be entirely dependent on the mon that happens to get it.
Its good on Mamoswine because Mano is normally weak to one and neutral to the other, so it loses a big weakness and gets a good resistance. This lets him use his typing to kill some fire types more easily, not get instantly destroyed by fire coverage, and he also has priority to snipe what’s weak enough to be finished off.
It’s amazing on Mega Venusaur because he’s a defensive wall that’s weak to both; gaining Thick Fat causes him to lose two extremely common weaknesses and shrug them off with his massive bulk, leaving him only vulnerable to psychic and flying. He can take full advantage of it and destroy opponents of those types by way of either attrition (wearing them down) or endurance (being able to take less damage and hit back hard).
It’s also good on Snorlax if you’re not running a berry gluttony set, but on most other Pokémon, the ability just really sucks. Not because Thick Fat is bad, but because they can’t make use of it. They either have better options, or it provides them meaningless benefits they can’t use or don’t need.
While everything still remains to be seen, judging from what’s been shown so far, I have the feeling that Celtitan will fall into the former category (having better abilities to use).
