IIS app pool limits to keep in mind for SharePoint

Depending on your hardware configuration IIS 6.0 does have a potential limit to the number of application pools. The TechNet FAQ for IIS stated here says:

The answer varies depending on the hardware and software configurations of your server as well as the types of content it hosts. If you are setting up your application pools with unique identities, depending on the applications and memory resources of your server, you will reach a limit of about 60 application pools. There are finite limits to some system resources that are allocated with each new logon session. This means that 60 processes can run concurrently as distinct accounts. IIS 6.0 supports running these processes in a single shared desktop, at a cost of sharing a single encapsulation of a user session among all parties.

There is a way to scale far beyond 60 worker processes, but why would anyone want to do that?