Beneficially means “in a way that has a good effect” or “in a way that helps.” If a change affects you beneficially, you are better off because of it. The word is a little stiff; people often just say “it helped” or “in a good way.” Lawyers also stretch it: to own something beneficially is to enjoy the real use or profit of it, even if another name is on the paper. Learners usually meet the everyday “with a good effect” sense first. Though actually, do not confuse it with beneficently. Beneficially is about the result (the thing did you good). Beneficently is about the giver’s kind action.