In message , at 11:26:35 on Sun, 27 Feb
2011, tim.... remarked:

why would a child want to pay adult Oyster fares when they could buy a paper
travelcard for less?

Part of the attraction of the scheme is not having to queue up to buy
tickets (and also not needing to know the system well enough, including
speaking English, to be able to decide which tickets to buy).
--
Roland Perry