If anything at a minimum ebucks will typically cover your monthly bank charges so in this case the lunch is actually free.
I've done the maths before and the low cost or near "free" banking accounts from all banks charge for things that are free on "expensive" accounts, to various degrees - like debit orders, swipes, cash withdrawals, deposits etc, which means despite costing less than say a Gold Cheque Account with credit card its not by much and then you lose the overdraft, credit card and ebucks.
An overdraft really is an amazing thing, compared to a typical loan its ultra low cost and easy to access. No one should live on an overdraft but every so often it can be a life saver.