They don't build deck around Figure of Destiny , but decks like Boros or Zoo use it as part of their strategy.
Figure of Destiny is a playable card in Modern. That, in itself, is a very high honor for a Kithkin.
Definitely usable in modern... though not necessarily a staple. cards without as much required input such as Kird Ape , Loam Lion and Tarmogoyf tend to be higher on the priority list for modern deckbuilders