With the popularity of Commander growing, cards such as these will begin to creep up in price due to demand
Dualcaster Mage paired with Twinflame can create an arbitrarily large army of hasty Dualcaster copies
Both sides of Valki are excellent, with Valki being hand disruption useful in the early game to steal a powerful creature (with the potential to turn into it later), while Tibalt is a great end-game card, capable of removing multiple creatures and stealing cards from your opponents' libraries to cast yourself
Maintaining a large mana base, along with the Treasure tokens, is one of the cornerstones of the deck, especially later in the game when many cards have already been exiled
Trust me this doesnt even scratch the surface of what this card can do
I suspect they wont see a lot of play outside of more budget lists, but theyre really nice