The Reserved List solved an existential crisis back in 1996, but because it promised that the cards on the list would " never " be reprinted (and because Wizards has mostly kept this promise for 25 years), it has ended up causing problems in the decades since as we are stuck with a supply of Gaea's Cradles, Underground Seas, and Lion's Eye Diamonds befitting a game with hundreds of thousands of players for a game that now has 20 million
He's basically saying "play as many cool artifact creatures as possible and go to town." With a deck like that, it's largely just about upping the overall card quality and filling some holes that may have been present
Meteor Golem Spine of Ish-Sah, but can't target lands (why???), doesn't have a neat built-in recursion trigger, buuuut it's a creature so that opens up more synergies
So they, they have a particular tang and, like, feel to them