[joestrouth1]

If one user kept their files in the root directory, where would a second user keep theirs?

[codedokode]

In /ubuntu24/home. Or a subdirectory could be created in the root directory.

[aallaall]

Most operating systems mounts things dynamically. You can never trust that a path for you exists for another user.

[pwg]

This is a very recent aspect time wise in the very long history of Unix (and Linux) systems.