^Look closer, they each point to flights out of San Francisco to those worlds. And a transwarp network would explain the extremely fast travel times in the new movies, should one insist on using the warp factor cubed formula as a baseline.
That said, you're right it was only ever intended to be background art. But a piece of background art I've had a great deal of fun analysing. Trek referencing Trek is nice after Mike Okuda's endless non-Trek references in TNG screengraphics.