I now realize that I don't miss out on something very clever by not using the multiple library feature. I can finally relax and start reading again.
Edit: But I quicḱly started to worry again...
We now have the ability to switch between libraries. I suspect that Kovid at some point would like to avoid testing this using the set of libraries that includes the library he uses for his personal reading. So we might perhaps expect a feature where we can choose between more than one set of libraries. A reading set and perhaps several debug sets. At the click of a button you get another list of libraries.
Just imagine the amount of threads with questions that could lead to.
And there really is no need to stop there. We might later want to choose between different groups of sets of libraries. And so on...