There are 2 different options :
- "Windows - WinSxS Backup
Folder Cleanup (install.wim)" : the "Backup" folder is a non necessary folder, without important troubles in your WinReduced system, so this may be seen as a "small" WinSxS cleanup without breaking windows functionalities ... this is why there is none description in the help tips about possible troubles
- "Windows - WinSxS Folder Cleanup (install.wim)" : in the contrary, this option have an important reduction impact in the final size footprint but also break a lot of windows components, as described in the help tips ... This is why the help tips mentions "ONLY RESERVED TO EXPERIENCED USERS" .... but, for example, in my own case and using my "Desktop (Extreme)" wccf, I always use this option because I do not want to use "Windows Updates", I prefer installing regularly a fresh system with all new updates integrated in my WinReduced system.
And the same description can be applied to the options dedicated to "boot.wim".