The application in tournaments would be as a "hatebear" and not part of a hard lockdown. She hoses a lot of popular tournament cards. In Vintage the effect is especially pronounced because most decks use 0-drops and use nonland mana sources. Most decks run a smaller number of lands compared to other formats and a lot of decks use lands that produce 2 or more mana. So opponents will be slowed down. Not locked, but hobbled sufficiently to make this a severe threat. The most notable downside is probably that the effect hosing 0-drops is a nonbo with Thalia, Guardian of Thraben. But I think that the card is still so potent it'll see play.
Oh, also quite relevant in Eternal formats: those abilities are asymmetrical. You can cast Force of Will by paying a life and pitching a blue card, but your opponent cannot. You can drop a Mox, but your opponent cannot. You can delve away your graveyard to cast Dig Through Time, but your opponent cannot.