It is, this infographic is wrong. Or I guess technically some other standard could define it like the infographic, but the Filesystem Hierarchy Standard defines it as a secondary hierarchy specifically for user data.

Specifically, these are for being able to pass in the tubing when your computer overheats playing Counter-Strike 1.5 so you pull apart your 50cc moped so you can bolt the moped radiator to the side of the case since it doesn’t fit inside. At least that’s the only use I’ve actually seen in practice.