Paradoxically, employing more checkouts will appear to lower productivity even as it raises payrolls. Critics of America's more flexible labour markets claim that productivity in America's services are lower than in Australia. This is probably true if you measure it in terms of customers per worker or goods sold per worker. However, employers do not hire for the fun of it. These workers are put on the payroll to service customers, which means that customers tend to get more service, e.g., faster service.
Time is scarce and thus valuable, especially for working mothers.
It's a pity critics of American labour markets don't take this fundamental fact into account.