Installed Software Question

I would like to import .net framewrok into a package. I know how to do this and set it up to deploy etc. My question is what relevance does it have to the 'installed software' entries under newly discovered software.  (see screenshot).

If I have .net 3.5 sp1 - do I just click on one of those entries and click manage this software. ? what happens to the other entries ?

What are the benefits (if any) of doing this rather than just importing a package from new ?

Thanks