Fast and lightweight software. Who needs it?

Over on Techcrunch they have this Bram Cohen quote:

“Moving forward behind the scenes, we will continue to develop µTorrent and will be using the codebase in other applications, especially ones where a fast, lightweight implementation is more suitable, such as embedded systems on TVs, cell phones, and other non-PC platforms.”

 When are fast lightweight implementations like uTorrent not suitable?

Link to Techcrunch » Blog Archive » BitTorrent to Acquire µTorrent