Flying
As long as Archangel of Tithes is untapped, creatures can't attack you or planeswalkers you control unless their controller pays {1} for each of those creatures.
As long as Archangel of Tithes is attacking, creatures can't block unless their controller pays {1} for each of those creatures.
If you control an untapped Archangel of Tithes, your opponents can choose to not attack with a creature that must attack if able. The same is true with respect to an attacking Archangel of Tithes and a creature that must block if able.