It probably saves a ton of space and tidying, but at the expense of needing more staff to serve.

It would be beneficial in total labor today, especially in a store with employees picking for curbside exists. Stocking is a big effort overnight. Restocking is problematic during the day, and costs sales. These normal processes (busy people doing stocking and ordering, and inventory existing in 2 places) makes ordering harder. If customers would accept the change it might happen. The rub is studies show customers don't like it, and no browsing means lower sales.