The Mid laner pretty much does it all, it’s kind of like the sample platter of all the different roles. You’re a solo 1v1 lane like Top, you can influence many parts of the map like a Jungler, and you’re expected to be given gold and carry like an ADC. You have to worry about last-hitting and farming but you also have to be ready to react to help other lanes by roaming, aiding in taking/defending objectives, or participating in action in the Jungle. You can even play similar to Supports with champs that have shields like Orianna or Lux.