I "always" bought the idea of the little craft as a tractor-beam tug, because it seemed so ill suited for anything else. No access hatch for surface disembarking, for example. Little in the way of landing gear as well; the matte in ST4 shows the craft rather precariously perched for maintenance. And the little figurines in the cockpit wear spacesuit-like working gear...
That matte scene is a bit weird, though.
We see no fewer than three of these working vehicles swarm around what is supposed to be a group of VIPs, delegates or other bigwigs, in a really cramped setting of clustered office-like buildings and tarmac marked with yellow lines for guiding vehicular movement. What is this place? The backlot of a shuttleport?