It just so happens that the slivers of the Onslaught era weren't great, and it ran a bunch of weird one-offs like Decree of Justice and Silver Knight that saw play, but ignored the context of why they were good in the first place
While they are stiff and hard to open at first, they break in nicely
While actually comboing with Glorious End in Commander seems hard (but let me know if you have other ideas!), it seems like the card will see at least some play in the format
Still, the fireworks reverse holo version of Zam is striking and its understandable that its worth over $150 on the secondary market
Of course, this high level of collectability around the games cards, not to mention ever evolving, compelling mechanics, is what has kept Pokemon near the top of the food chain when it comes to being one of the best trading card games in the world