3) Also, the error rate on them was astronomical.
Twice I've undercounted when paying in, once was only by £20 but the second was £100. If I'd used the self service till I wonder if the person checking the amount would think 'they've paid in £100 more than they've said - I'm having that'.
But what if it's the other way round, I pay in £500 and put £500 on the paying in slip but the cashier miscounts and says I only paid in £400, what comeback would I have, how could I prove I actually paid in £500 ?