TBH I don't think the other psychics can actually help. There seems to be different types of these "spirits". The ones that bring bad luck to a place, i.e. the haunted place that turned into a successful shop after they got cleaned out when Hana went in to save the dog by the thing following her, and ones that get stronger by eating other "spirits", which is present in the same example. The issue is that the granny does not see the ones that eat others to become stronger, and we aren't sure of what the extent of the male psychic's powers are. The shrine maidens with the big one probably belong in the latter case, as far what we are presented with. Since the granny cannot see the big one, she most likely did not ask them to help her, in which case her experience with them is probably completely different.