Back in the days before Windows 8 and Server 2012, all the patches would quickly consume lots of disk space in the windows installer folder, due to caching of all the files, to make it possible if you needed to uninstall patches.
A common fix back then was to delete the contents, either manually or through some 3.part tools, which could cause inconsistency.
In win 8 and server 2012 Microsoft invented the Thrusted installer and TiWorker process to, among other stuff, maintain the WinSxS folder like cleaning up duplicated or orphaned files and compress the remaining folders.
In addition to that .Net precompiles its intermediate code into native machine code for the updated parts.
Sound pretty good ehh? Well it has some drawbacks…