I don't have a desktop per se. I use laptops exclusively at the moment. A Nano-ITX box may change that soon.
Just because I own a faster machine which I use most of the time doesn't mean I don't want VL-Light or VL-Mini. I still own two Toshiba Libretto SS1010s, each about the side of a paperback book. I am considering an Asus Eee PC as a replacement for one or both, but... the Libretti still can do a lot of work. Their specs: Pentium 233MHz processor, 96MB or RAM in one, 64MB in the other. I'm not about to throw them away. Trimming down VL to run on them is a pain but it works well in the end. A newcomer to Linux couldn't do it. Having a ready-to-go slim VL is a wonderful thing. Kudos to the developers of the light versions.
VL has a long history of catering to low end machines. It's how this distro got it's start. Don't get me wrong, I appreciate the new 64-bit version as well. I just think having this variety of versions, all based on the same code, is a good thing.