Secret Rare status combined with Gengars massive fanbase has pushed it into the spotlight, reinforcing how certain Pokmon with lasting popularity translate directly into collector demand
Before investing, also consider are Pokmon pull rates getting worse over time, and Pokemon sets ranked by pull rate shows which current sets deliver the best opening value by expected return - declining pull rates in reprints can also suppress demand for opened product, indirectly affecting sealed values
It still requires multiple visits to the trade tab for both traders, which again, sucks, but at least you can trade asynchronously, on your own time
It can even be used to target your opponents and their creatures if you need to put them in time-out
Were leaning more towards Zoroark and the Eeveelutions because they provide a way to combat Volcanion and stop it from burning Golisopod to a crisp