What's the Use of Feeling?

Sacrifice an untapped Gem creatures you control:
Create a tapped Gem artifact token with "{t}: Add {c} ."
Gem artifacts you control have "{t}: Add {c}{c}. Use
this ability only when convoking and the mana can
only be used to pay mana for convoke.
{c}{c}{c}{c}{c}{c}{c}{c}{c}{c}{c}{c}, Convoke: Search
your library for a Diamond and put it in your hand. Shuffle.
Tell me, what's the use of feeling, Blue?
—Yellow Diamond