NPC's are never useless in that one of their most important beneficial factors is distracting the boss/enemies. I would still want to summon an NPC that didn't even do damage, because honestly they all seem to do not much more damage than none in the fights, but again, that's not why they're so important.
If you got her to spawn skeleboys, rejoice. Kill all but one and stick to her like pine resin so she is more occupied with hitting you with her scythe than spawning Verstadt. Also stripping down to my skin suit to maximise rolling helps somewhat.
It really doesn’t have that many ganks especially compared to basically every other fromsoft game. In fact, comparatively, it has the fairest ganks in the series since all the enemies have the same exploits and weaknesses that you do. Unlike ds3, where the same weapon does like 3x more damage for them as it does for you while they have nigh infinite stamina and unfair poise.