I don't think it steals SP ability like Larceny but many mob self-buff effect are quite potent. Giving that to EVERY party member in range maybe isn't extremely usefull in every fight but still i can't say it's completly useless. It sounds far better than a 1hr Absorb-stats that we were expecting to me. We don't know anyway, if it's really linked to Astral flow that would make it quite bad.