Yes. If you want to buy a £2 DLC thing, and have no credit, you need to credit £5 minimum to buy the £2 thing. If you then want to buy a £4 thing, you have £3 in credit, you need to add another £5. But if you want to buy something for £6.39, you can pay exactly £6.39. In that respect there's zero overhead. However, due to an accumulation of leftover pennies, I did end up buying a 20p avatar just to make use of 20p credit!
This is something easier to manage with cash versus points, but you could do similar with points if direct purchasing of points was allowed.
As for transaction costs, card fees aren't that high now that banks have sorted out microtransaction fees. PayPal offer a microtransaction fee structure in addition to the normal one, better suited for selling very cheap items. I'm sure a huge volume seller could negotiate good deals.
This is something easier to manage with cash versus points, but you could do similar with points if direct purchasing of points was allowed.
As for transaction costs, card fees aren't that high now that banks have sorted out microtransaction fees. PayPal offer a microtransaction fee structure in addition to the normal one, better suited for selling very cheap items. I'm sure a huge volume seller could negotiate good deals.