Yes this is the cache directory. Not only is the JRE stored there, but also all of the jars required for launching etc.
You could place a redirect.txt file in that directory to tell the launchers etc to use a different directory if you want to share it across multiple users. There is a post about it here
It should be noted that the configuration of the launcher would be there as well meaning all users’ launchers would rely on the same configuration which may or may not be desired.