Corner libraries are the way the library can test the waters and see if there is demand for a fully established branch in the community. North Boulder is an example, which established a corner branch in 2014 and is now (via a dedicated tax approved by voters as well as other gifts and investments) slated to expand to a full branch in 2022 (although stable funding such as that provided by a library district will be needed to fund the operation of this branch long term).
Corner libraries do incredibly mighty lifting as community centers and gathering spaces -- the NoBo corner branch is one of the busiest spaces in all of North Boulder. Corner libraries can conveniently bring books right into your neighborhood from other locations and save you the trip downtown of dropping them off. They can offer literacy classes, Spanish classes, storytimes, and all sorts of community activities. Many people plan their outings around corner libraries - they might visit the library, bike to the cafe, stop at the grocery, etc. This creates a greater sense of community and belonging.
Corner libraries, like all neighborhood libraries, are not only community centers but economic drivers as well. It would be amazing to have one in Gunbarrel and other outlying areas!