Staff are still on the books so that the business doesn't have to go through all the paperwork of firing (and possibly re-hiring when business resumes).
In addition to the cost of paperwork, there's also the issue of paying out unused PTO. In many cases like mine, this can add up to many thousands of dollars per employee.
Staff are still on the books so that the business doesn't have to go through all the paperwork of firing (and possibly re-hiring when business resumes).