I have been doing this for decades. My files are in a sub-directory of $HOME. It also makes it very obvious when a piece of software does not treat your $HOME with respect.

"/home/${USER}" for whatever junk programs are going to stick there, "/home/${USER}/home" for my "real" home directory.

Always... Except for the decades before this became common. Never a bloated C: root directory. Microsoft even had games store stuff in My Documents\Games at one point. My Documents was a user dir that saw a lot of abuse over the years.