Personally, I'm not - just because I've never did anything worth being put to repos (this may change soon, cause I'm working on some thing). Still, as experience of some prove, using autobuilder to put packages into extras (AFAIK it packs it as .deb on it's own) is a matter of reading it's instruction and following relatively simple steps, i.e. anyone who get her/his a** up and read README can do that. Just keep in mind that I'm quoting popular opinions here, not my own experiences. Although, it seems to me, that most of non-repos things are out just because devs were too lazy to even check how easy/hard using repos is

Of course I'm not attacking anyone, but something tells me that - honestly - non-repos developers didn't even tried to put something there. Anyway, for sure it's much more easy than creating program in first place.