Agreed! - If you have the disposable for the capital outlay, who cares what the mpg is given the tiny mileage that most of us do.
I think it's more of a psychological thing
- I can press the button transferring say £40k to buy a car without batting an eyelid, but paying £50 quid in folding at the forecourt, for yet another Plus 8 top up would irritate.
Why do we fanny about with Tesco cards and buying baked beans in multi packs to save a few pence when we spend £££'s on a sports car???
Hope
don't read this.
You know it makes sense! 
