It's a great card, but the big caveat is that you really need four of them in your deck, and that's a lot of space. If you're already running 4 VS Seekers, 4 Sycamore, 4 Ultra balls, 4 Trainers mail.. it adds up. But just one is pointless, two is madness, three is a huge risk with discards and prized potential - so you need the full count of four.
Where it really shines is either in fighting decks where you have Korrina anyway - so you see one in hand, and she grabs you the other along with a mon, and now you have two of their many support cards back from the discard - or else in decks with low HP mons and you are expecting to take hits early and often, and now you have full access to both your deck and discard via Teammates. Teammates even grabs three cards potentially if you already have one PoT in hand - the second PoT plus one more card, then two discarded cards too. Decks with low HP mons though, tend to be evolution decks where space is at a premium. So the card is quite balanced thanks to the space cost of needing four. Meaning as ever, Night March is the big winner.
Really though, any deck that relies on some crucial mostly un-retrievable card, such as a low count of special energy, or a rare candy, can benefit hugely. So long as you can find the space for it.
