Oh, he definitely has that function and I think one of the reasons may be that he is partly human himself and so may understand us a little better than his fellow Gods—what makes us tick, what gets our attention—allowing him to slip through our defenses and awaken us to the wider world around us. Or maybe not. What do I know?
I know he is a very generous God who loves his family; his myths are filled with accounts of him coming to the aid of other Olympians, raising mortals up to divine status, building temples, introducing cults and serving other Gods in a priestly capacity. That’s a pretty extraordinary thing when you think about it; most Greek Gods are eager to elevate their own dignity and thus are not inclined to humble themselves in the service of others.
So really what a lot of people recount today—Dionysos coming into their lives merely to turn them over to another deity—is sort of an extension of that ancient tradition.
Plus, well, Dionysos is sexy, exciting, mysterious, dangerous, etc. so it’s not a huge surprise that he’s great at getting our attention.