Archangel of Tithes asks opponents to budget mana for combat. While she is untapped, each creature attacking you or your planeswalkers costs its controller one mana. While she is attacking, each creature that wants to block also requires a one-mana payment. That makes the Angel useful both for slowing wide attacks and for making your own combat harder to defend.
The untapped condition shapes how you use her. Leaving her back preserves the defensive tax, while attacking switches attention to the blocking tax and normally taps her. Granting vigilance can keep the defensive effect active after an attack, and Drumbellower can untap her during other players' untap steps for later protection.
White creature decks with evasive threats can use the blocking tax to complicate an opponent's mana decisions. A player may have enough creatures to block but need to choose between paying for those blocks and keeping interaction available. The tax does not make blocking impossible, and opponents with abundant mana can pay through it. Three required white mana makes the card more comfortable in heavily white builds. It also does not tax attacks aimed at other players, so it protects your position without slowing every combat around the table. Pair it with an actual attack plan or a board worth defending. The strongest turns are those where the tax changes which blocks or attacks opponents can afford, creating a useful opening for the rest of your creatures.
