And what do I get out of it?

I've complained about this before but I'm going to rant again. Why am I charged a booking fee when I buy concert tickets? What do I get out of it? What value is it adding to the ticket buying process that makes it worth paying? And most importantly, how on earth do they decide on the level of the fee?

I recently went online to buy concert tickets and here's a screenshot of the booking fees:

How does that make sense? If I go for the ticketFast method, I spend time at my computer, I do all the work, I spend a fortune on ink (possibly the subject of a future rant), and I pay for the paper. And for the privilege of spending all this time and money, I get charged £2.25. That hardly seems fair!

But then look further down. For the venue to pay someone to stand in the box office, to print the tickets for you and using their ink and their paper, only costs £1.50. How does that even begin to make sense?