There is an okay amount of creatures with this type and I suspect they will not be very high picks for other archetypes, thus you can hope to get rewarded later in the booster if you find yourself in White-Green
Youre turning Nami into a 7,000 Power Leader, making it difficult for your opponent to get their attacks through
For two mana you get to put a +1/+1 counter on a creature, giving it both deathtouch and indestructible for the turn
They can also destroy any permanent (Angel of Despair), gain you life (Angel of Mercy, Lightkeeper of Emeria), destroy many creatures (Sunblast Angel), save creatures (Adarkar Valkyrie, Twilight Shepherd), reanimate (Reya Dawnbringer, Karmic Guide), keep alive indefinitely (Platinum Angel), shut down abilities (Linvala, Keeper of Silence), destroy all lands (Desolation Angel), give your creatures Indestructibility (Deathless Angel), and proactively prevent all combat damage (Blinding Angel)