>>50333535Ghost is only resisted by dark and the immunity normal type has on it is non-existent as normal type are pretty much cryptids in higher tiers. This puts it in a similar position to the pre-gen 6 dragon type.
Ghost is also good defensively, it blocks rapid spin, resists U-turn and is immune to one of the most common type of coverage moves. It's no poison type but it's definitely not mediocre.
Also poison being able to fuck fairies is unfortunately not enough as the only other type it hits hard is grass which is pretty mediocre. But it's even worse when you realize that it is resisted by4 types : poison, ghost, ground and rock and cannot touch at all the steel type. Being able to hit the best type in the game isn't enough to make up for that.