I'm still confused on how that Pokepuff is a good card... You are almost helping the opponent. I guess it could work for a huge hand with shaymins in it, or it could bring out easy Lysandre targets, so it might see some play
1) you get to look at your opponents hand
2) you can force them to bench Shaymins (or Hoopa EX) which become great lysandre targets AND wastes them if the opponent has a reasonably big hand
3) you can bench night marchers to severely lower the maximum damage of night march which is BDIF (or bench other pokemon that want to go into the discard, such as vs Vespiquen or Exeggcute)
4) you can fill up the opponents bench paired with bench limiting stadium, resulting in them not being able to power up a suitable backup attacker OR not being able to bench their crucial bench warmers
5) you can fill up the opponents bench to increase the power of attacks which improve with the number of opponents benched pokemon (such as Zoroark, Lucario)
6) you can bench pokemon to allow for copying attacks from your own pokemon (Zoroark BREAK, M Gengar EX)
7) you can lower the opponent's hand size and then play a disruption card such as Delinquent, or Ghetsis in the non standard format to severely drop their hand size
8) you can get around a solo Jolteon EX by forcing them to bench another pokemon
i wouldnt put it into every deck but i think the above merits are enough to place it in some decks