I am right in saying you have to pay for the waiting area as well? If so, there really is no hope!
You get paid £4.80 extra for picking up, which comprises of £3.80 for the short stay car park, and one hour waiting in the AVA. If you're waiting for longer, then the extra will have to come out your own pocket.
Most of the time (on UberX, UberXL can be quicker if you get an XL job first), you're not normally there for longer than 2 hours (so you just pay an extra £1), unless there's 200-300 cars there, and its the middle of the day (as opposed to the am/pm rush).
As the OP says, most people I'd imagine do it because of the ease of doing a motorway run, and the pick up, is relatively straightforward - though this relies on both driver and passenger following the simple instructions on the app.
Some just wait at the airport, immediately after dropping off there, for a rest and bite to eat etc, before getting a job back into town.
The regulars probably just like going there to socialise, I expect. The queue position counter also gives some degree of certainty that you will get a job eventually (rather than waiting in town with no certainty of getting a job at all).
Exec/Lux drivers often wait for hours for a job, but most of these use Uber as an additional income anyway, and aren't bothered by the wait, otherwise I don't see how they can make money.
