I don't see Juniper's Dad being played in serious tournament decks, especially with Cheren doing the same thing except without the chance of giving your opponent the benefit instead. It could see some league play though, particularly by (and against) new players.
Why "Juniper's Dad" though? He has a name, Cedric.
In Japan, he is simply known as Dr. Araragi. He is not given a first name in Japan.