Those are some strong cards, but they aren't Top Ten quality, amiright
Synergy means cards working especially well together
It has similar advantages to cards like Yawgmoth's Will or Past in Flames when youre going off in a storm combo, and you can also mill yourself and win with Thassa's Oracle
Gamestop can plausibly argue that it's just engaging in what economists call pricing equilibrium , raising the cost of the cards to better reflect their true market value, but as Rutherford points out, this also puts the cards financially out of reach for a huge chunk of the intended Pokmon card consumer market, who aren't in fact collectors flush with cash but children and teenagers eager to play a card game
Its not especially exciting, but its useful, especially with so many artifacts in this set
Graded Population Report: Pikachu #58 Visualize the distrbution of grades in the chart