Hi,
.NET is basically just a toolkit for programmers. It allows them to cut a few corners and write a few lines of code where they would otherwise need tens or hundreds. The side benefit is that it means their code is more consistent and perhaps even more stable because they are re-using ready made code for frequently used function.
If you've got software that has dependencies on it, it's probably worth keeping it updated. Otherwise I guess you could try to uninstall it and see what breaks !
I'll see if I can dig up a way to track down dependencies.