You have to tap those tokens to use them, so it does limit your ability to use things like Treasure and Clue tokens, but does give you the opportunity to keep everything open until your last opponent's end step to start using Baylens abilities
A mana dork that adds two and lets you cast from the yard is great, and menace is even better for triggering treasure generation from attacking or dealing damage
Additionally, her special ability allows any challenges from your opponent that happen while Tiana is exerted will give the challenging character a minus three to their Attack
In my opinion, that moment begins with the HeartGold & SoulSilver (HS) expansion
The ability to shift all energy from one weakened Pokmon to a new, powerful Pokmon can mean a monumental shift in the course of the game
If nothing else, you can just copy the draw trigger and get extra cards that way, and the ceiling is much higher