It also very much changes perceptions. I used to work for a company that manufactured point of sale systems. They found they could improve the amount of time the customer waited by queueing up all the printing of the receipt until the end of the transaction. (This was in the 1980s.) They could save something like 10-20 seconds per customer, which meant they could move 1-2 additional people per checkout per day. (And the store had something like 10-20 registers - it was a huge store.)

However, customers hated it because it felt like it took longer. They would be done with their transaction, done paying, then have to way 10-20 seconds for their receipt to finish printing. So they'd be standing there just waiting to leave with nothing to do. The company had us change it back to printing each line as it was entered into the computer.