Marketing. So they can say stuff like 'send your photos 10 times as fast!!1!!!1' when the speeds they are increasing has nothing to do with sending (BT's ad

).
Just about what looks better i guess, who offers the better service. Capping will always be small print, the 'catch' to the service; all the big companies seem to have gone all out on maximising customers with capping.
But, ic24, i still remember the days of relentless redialing and the joy of when i got through