I must be a lot older than you (which is true of most other posters here, so I guess it's not surprising) because those compilations came "later" to me. I think even the "Beat the Boots" series predated them, didn't they?
A lot of the fun of a new Zappa/Mothers release was... well, first finding out that it had happened in the first place, as this was pre-Internet. Then figuring out what "kind" of album it was. Was it live, studio, or a mixture? Was it instrumental, crazy stuff with vocals, jazzy, electronic, or what? You never knew for sure, and all you could do was guess.
The first Zappa album I bought was Sheik Yerbouti, which was a hybrid album. The liner notes were extensive, and included whether each track was recorded live or studio, if there were overdubs or not, or just a few, where it was recorded, and sometimes who played what. There are pieces that were literally composed in the editing phase. The bass track from one recording extricated and synched with the drum track from another to form a duet, and in the notes he points out that "all that sensitive interplay never actually occurred". Holy shit! It was like a glimpse into the mind of a musical sculptor or something, someone who didn't just write, perform, and record music, but actually created it, and invented his own methods for creating it.