It provides one of the most powerful effects in the game (promoting one of your opponents benched Pokmon to the active position) without needing to use your supporter for the turn
It's scratched an itch for strategy, silly fun, counting, cuteness that I didn't know I had
The strongest starter deck in terms of competitive potential is Black Marshall D
Instead of a beautifully drawn portrait, its more of a scribble in the vague shape of a Doduo, like the artist drew it from memory or with a blindfold on
In fact, we want it enough that Cornered by Black Mage is basically a two-for-one play, like a black mage Nekrataal
This style of flicker deck usually favors a commander who can enable flickering itself, and you can review my selection of the best commanders for enabling flicker decks if that is your preferred style of gameplay