Why are creative cloud libraries not on selective sync download?

Instead of all CCLibs downloading to my computer - why aren’t they available as selective sync like Google Drive or Dropbox? Libraries are for differerent purposes, different projects, different apps, different clients etc - users do not need all of them, all of the time, taking up lots of local drive space -  when they already in the Adobe cloud. 

I’ve been told in the past that users are able to remove from the cloud and store on an external hard drives etc to save space if so desired - which seems a somewhat backwards solution.

Selective sync please!