Use Of Filter packs 2.0 in SharePoint 2010 prerequisite

One of my friend asked me that what is the use of Filter packs in SharePoint 2010 prerequisite.
After googling, I found  following:

The Microsoft Filter Pack is a single point-of-distribution for Office IFilters.

IFilters are components that allow search services to index content of specific file types, letting you search for content in those files.

When crawling content, the crawler uses an IFilter to read individual file types

They are intended for use with Microsoft Search Services (SharePoint, SQL, Exchange, and Windows Search). 

From This MSDN link you can see File types (that appear by default on the Manage File Types page in Central Administration and describes whether their corresponding IFilters are registered by default) and IFilters reference (SharePoint Server 2010).