First of all there is Parasect SV
The ability to use it at instant speed to find a combo creature, destroy a creature, or exile an artifact or enchantment is incredibly useful
There are a select few cards that have been banned from tournament play
Even if its a little bit bad, or missing some potential, its undoubtedly for the better these decks exist
The rare version, Glistening Oil does the same recursively, but slowly shrinking our creatures will often feel bad and can backfire
Most Basic or Stage 1 Pokemon will not be able to survive a full Bench Circle Circuit and that is where Pikachu EX can dominate a match, taking down threats before they emerge: it doesnt matter if your opponent gets lucky with their Moltres EX and stacks energy on their Charmander if you can just knock out the Charmander or Charmeleon before it becomes a Charizard