Slightly surprised that nobody here, (or MSE when I read it) has suggested the commission angle.
Betfair have a shite commission rate of 5% for average joe. I was led to believe that this in part is down to free MB payments (hence Betmate being 3% and charging for MB transactions).
Betfair seem to continually want their cake and to eat it also?
I hasten to add that this is very unlikely to affect me at all BUT if it does, I'm gonna be a tad pissed at proceedings.