There are a LOT of conversations that happen during product development with a number of different factors considered, and the inclusion of mechanically unique cards is one of them. Honestly, the art is beautiful, the treasure token is great, and we love to see the OG Lara Croft design in a card
In addition, hes also a commander that comes with, and makes use of, +1/+1 counters, a very well-supported mechanic that can quickly get out of hand in a multiplayer setting
A stronger Infernal Grasp that exiles
I can promise you that Mark Rosewater is not going to teleport into your kitchen and shame you for proxying your Underground Sea rather than spending hundreds of dollars on a real copy
In addition, there are 5 basic lands with three unique variations each