I made a separate user for using Steam (and other games), and it involved a little bit of routing when it comes to X11 and PulseAudio. My reason for doing so was primarily because of how games create many dotfiles, and I wanted my home folder clean.
https://wiki.archlinux.org/index.php/PulseAudio/Examples#Pul...
Forgot exactly what I did with X11, but one part of it was having an environment variable that used my main users XAuthority
E.G. [gamer@mycomputer]$ echo $XAUTHORITY
/home/notthemessiah/.Xauthority
"Those who do not understand UNIX are condemned to reinvent it, poorly." -- Henry Spencer, programmer
This goes doubly for "containers" not understanding chroot/jails.
Containers provide chroot-like behavior for more than just the filesystem. Processes, user IDs, network interfaces... Chroot is filesystem only.
If only chroot was enough, noone would be investing their time to the cgroups, namespaces, LXC, Docker, etc... :-)