It's just an example of one of the many over sites in the pack, the rest can be noticed when using high end video production tools.
As a general guideline don't install codec's you don't need.
But to each their own.
On win 7 the only codec I have needed to install is RealAlt so far the rest has all run on gom, I intend to keep it that way for a long time to come.
There are a long list of reasons but with out getting into a 30 page diatribe on the subject suffice to say I have worked with conversion engines and video codecs for some large companies and know a "little" on the subject

- But if I was going to recommend a pack -
http://shark007.net/ I would also recommend using G-Spot Codec Appliance to get specific needed codecs, before trashing your system with home grown stuff in packs which is not always of the best developer standards.
But like I said to each their own