with an MDFC, you need to choose between getting the land or the spell, but you get both when send your land on an adventure
There's some decent value at the uncommon level with cards like Slip Out the Back and An Offer You Can't Refuse
But if you have to move Gloom into the active Pokemon spot before evolving it into Vileplume, or you moved Oddish into the active Pokemon spot and evolved it into Gloom, I would always use Poison Powder as long as you have three energy cards on Gloom
If, for any target, you can't choose a new legal target, then it remains unchanged (even if the current target is illegal)
And it's just a fun art to pick out every eevee and their action
Where this card really starts to take off, however, is that it can also function as a win condition