Sometimes it's hard to find a reason why certain cards don't seem to be as in high demand as others, and this Piplup card is one such anomaly, especially compared to the Pokemon that surpasses it
Accessibility: So-so Dragonstar is really easy to miss if you don't already know where it is, it took me a little while to find the entrance when I first went, so I think others might have trouble too, especially since there's no sign
Its design, along with Phelddagrif, later inspired the Apprentices and Masters of Invasion with its multiple abilities paid for with allied color costs
Modern singles from recent sets have corrected 20-30% from launch peaks, which is standard price discovery
Actually transferring control of permanents is not a common effect in Magic , so having that ability always accessible is a high priority
You can fairly reliably cast Gweena on turn two in other formats like Pioneer or Explorer, with one mana creatures like Llanowar Elves and Elvish Mystic to help ramp up to bigger cards like Craterhoof Behemoth