It's different here in the Colonies...
Usually there isn't a queue at the petrol pump here in the US. Only at times when the prices are moving around and one station is more than 5 cents cheaper than the others...which usually quickly match the price. So waiting for someone to pull a map or coupon isn't that big a deal.
This idea is actually in use already at many petrol station in the US, with adverts for stuff from the convenience store at the station being plugged on the LCD or scrolling text display. It works, not so much from the standpoint that it's inherently interesting, but it's cheap (read: free) and even a very small number of incremental sales drives people into the C-store, where the REAL profits are made.
Besides, it returns us in a post-Internet way to the "good old days" where maps of the local area, state and country were gladly given away by the friendly pump attendants, along with directions and suggestions for restaurants and hotels. (Yes, I AM old enough to remember those days!) But it will probably only work in America, or possibly the Antipodes, where there are petrol stations on nearly every corner, with 8 or more pumps and plenty of parking. (Some of the petrol stations in Mexico or Japan don't even have pumps on the ground, but hoses hanging from the roof and large displays of the pump info on a wall - no Googling from these locations!)
Finally, the HUGE complexes that provide diesel fuel for lorries here are very much prime candidates for this. Truckers currently have to leave their rig and go into the building for maps, payment, etc. - this keeps them moving on the tarmac and gives them information that they usually need to get via CB radio from other truckers. As well as plugging the services at the station and other local trucking business.
Nice idea, Google!