So the title might be a bit confusing, but sort of similar to how twitch emotes work, followers get a custom set of emotes, subscribers do, and so on.
This would be sort of the same for discord servers. Server owners can allow certain roles to use emotes. This would allow server owners to set up an ever better rewarding/leveling system. I think it would be awesome to give roles specific emojis and encourage users to do certain things in order to unlock some awesome emojis!