SKY HIGH STATES: Not only do carts expedite the service, but they make it more efficient. 3 Flight attendants serving 150 passengers. So, each F/A gets 50 people. That's how many up and down the aisles with a serving tray? TOO MANY.
I believe WN does it with 3 trips of 12 drinks per tray. Well you may change that to 6 as they are required to ask every passenger if they would like another drink even on the 30 minute hop from HOU to CRP. Not using the cart gives a more personal service and keeps the aisles clear for potty breaks