I mean its fine for dumb monsters who just eat people but not an intelligent race.. she couldnt feed herself- she couldnt have dressed herself.. couldnt build or make anything.. etc etc.
I remember watching an interview with an armless woman, one part of which touched on her being able to dress herself with only a stick attached to a suction cup for assistance. She'd also managed to ride horses, which is how she died(her foot got stuck in the stirrup when she fell out of the saddle).
But you're right that harpy civilization wouldn't be building anything too precise on its own(coarse building is just fine, given that birds tend to, y'know, build nests).