The charm of demos is that they’re unfinished; they’re the original song untouched by anybody except their author. Pale is an awesome instrumental and even though it has a form of a traditional song (intro, verse, chorus, verse, chorus, outro) it would only get worse with lyrics added. This song has come to a place where band couldn’t add anything despite unfinishness of it. All the lines developed in such way that adding another melody (lyrics in this case) would ruin the song.
On the other hand, Program and Broken Foot feel unfinished in the other way. They don’t have many instruments, in the verse there’s only a simple guitar riff along with drums which wouldn’t interrupt Mike’s voice.