>>11669767It's just a specific brick that scans stickers or chips in figures to make different noises. It's essentially the the Mario character figures without a display.
But outside of the character figures themselves, a lot of the Mario sets don't really seem hindered by the gimmick.
For some reason the Star Wars sets are making much bigger compromises to the builds. The Mario sets have little 2x2 tiles with stickers that barely look out of place. These things have giant discolored gaping wounds where you plug the brick in.