Well, it is nice that you are centrally located in the metro area. But with your app the list of libraries will include Orange, Riverside, and possibly Ventura, counties in addition to Los Angeles -- not necessarily applicable to residents in the outlying counties. And the wait times, whether through your UI or the individual library's site, are guesses at best since checkout durations vary and there is the ability to return books early.
I did not have a particular title in mind when searching, so I picked one from the home page of a library,
Jackie After O, and a large list of titles appeared that were not related whatsoever. Nice idea and UI, however.