Whats really good is that, on top of that, it also has both Prowess and Haste
And in a fun little nod to such a weird, unique creature, we actually saw Avizoa referenced 25 years later with Nael, Avizoa Aeronaut in Dominaria United
The upside of our milling counters is that they can deal with pretty much anything (outside of Shifting Ceretops, which we don't talk about here in Mono-Blue Mill land), for the fairly reasonable cost of three mana
For two mana, you get to take a creature from each opponents hand and choose to cast that card for as long as Valki remains on the battlefield
It can act as a mild deterrent for removal, especially with such a low re-equip cost
This spell doubles existing counters , which makes already large threats impossible to ignore