This is a common question that has surfaced at the same time reselling Pokmon cards became popular
As a rule of thumb the slabbed value should be 34 the raw price before its worth it
Now that Silver Tempest is out, Serena (Full Art) is listed at a more modest $42.98, according to TCGPlayer
With the amount of cards you can play from exile and the graveyard (not to mention the new Plot cards), Doc AurlockDoc Aurlock will be sure to see lots of play, both in the command zone and the 99 of decks like MuldrothaMuldrotha, Grolnok, the OmnivoreGrolnok, the Omnivore, Niv-Mizzet, SupremeNiv-Mizzet, Supreme, Gonti, Canny AcquisitorGonti, Canny Acquisitor, Riku of Many PathsRiku of Many Paths, and probably best of all, PakoPako and HaldanHaldan
Sin, Spira's PunishmentSin, Spira's Punishment has flying and a really interesting ability that triggers whenever it enters or attacks: "Whenever Sin enters or attacks, exile a permanent card from your graveyard at random, then create a tapped token that's a copy of that card