Do you know why the decision was made to print the common taplands with the Amonkhet symbol, but without new art that reflects the plane? Having Zendikar & Kaladesh art on cards with the Amonkhet symbol feels inelegant and makes my Vorthos side unhappy. I would've preferred something like the Welcome deck symbol, since the lands only appear in supplemental products. That said, Amonkhet is great and the prerelease was a blast! 🙂
The symbols are used to define Standard legality.