Brink has a tutorial posted on cleaning up the Win10 WindowsSxS folder.
Those same commands work on Win8.1 and possibly Win7, I can't recall for sure about Win7
With all the large ISOs and ESDs floating around some may be low on space. I hadn't checked the WindowsSxS folder of Win8.1 for quite awhile so today I followed Brink's tutorial and cleaned it out. I saved about 10GB disk space by running those DISM commands.
My Win8.1 WindowsSxS folder is now about 1GB larger than the folder in a fresh clean install of Win10/10074 :)

I was curious about whether extraneous files were saved in that folder on a fresh install and ran the utility on Win10.

No reduction so apparently cleaning the folder won't help with Disk Cleanup after a clean install