Speed of hiring
I frequently catch a mini cab from a south london station to the hotel I use mid week when working in the area.
The station has a black cab rank at the front who will want about £10 to get me to my destination
There is a mini cab office at the back of the station and almost always has cars waiting. It takes 10 seconds to tell the dispatch guy my destination and then i take a few steps to the waiting car. They charge £5 for the same distance.