Because I wanna be able to sustain my own populations, and they stay a good size for anoles to eat and they don't make any noise unlike crickets. I also wanna be able to sit the entire culture in the enclosure and just open the lid for a little bit to let some out at times when I'm not going to be home for a day or two.
Try searching farther back in this forum, the topic came up a while ago and they *were* going to be distributed at NWFF but they weren't ready in time. I don't remember who was working with them but I was interested in them for small geckos and treefrogs.
In terms of non-PDF animals, these are awsome to have in the hobby. Houseflies have been a favorite of many of my smaller gecko species (P. pictus, U. milli, day geckos come to mind), are well known for being great anole food, juvie chameleon food, and are also a great addition to the treefrog food menu. I've always had issues with trying to get aboreal animals to eat the terrestrial crickets, and having terrestrial geckos trying to catch flying houseflies.... we won't even talk about the hell when they got loose.
My only problem with using them as a 'vacation feeder' is the explosiveness of the regular housefly cultures I've worked with (I do not know if this applies to the flightless but I would guess it does unless there is a significant reproductive difference). You'd get a couple on the first day of hatching, then the next day the culture was covered every surface with flies. This is way too explosive for good feeding unless you were feeding 100+ feeder anoles (which is what the cultures were being used for). Then again these cultures weren't kept going like our FF cultures, they were just ordered housefly pupae. After the adults were fed out the cultures were cleaned and set up with fresh pupae. Flying houseflies are too much of a pain to deal with trying to culture (like trying to work with regular flying FFs).
The culture medium was rank I remember as well. Hopefully the new formula for these guys smells a bit better.