There are use cases where people might actually want to search the module list by keywords in their descriptions or even in the requirements/dependencies section.

One such case is when one needs to disable certain API-like modules that are used/required by other modules (and thus their on/off checkbox is not allowed to be clicked). One such module is the Chaos tool suite (ctools), but there are plenty others out there.

In order to disable such modules one needs to first disable all the other modules that use it. So they need to be able to search "by dependency" so to say. This proves to be a very tedious job and if the filtering was (optionally - though a checkbox) extended to the description/requirements section, it would then make it a lot easier.

This feature has already been discussed in this issue: #396478: Searchable modules page, but the general consensus seems to be to keep things simple and not include it in core.