/run is a temporary fs, so if the mount, filesystem or even the entire system crashed, all the mounted data will be cleaned up after a reboot.

On the contrary, if the mount crashed, it might leave a folder or data on /media, making subsequent mount problematic.

Here is a well-written comment about the rationale behind this mount point: https://www.reddit.com/r/linuxquestions/comments/tzo984/comment/i40e2za/

Probably so that you don’t accidentally write to a directory by mistake when it isn’t mounted, and then lose access when you mount something over it, all while services are looking for files that are only there sometimes.