Yes, for trace and contain. Right now we're totally in reaction mode, with hundreds of thousands of cases. In order to safely open anything, we need to be able to throw tens of thousands of tests out every time there's a case.
This has been bugging me specifically since my state is one of the ones that wants to reopen stuff, so let's take the example of Texas state parks. A couple things we know - people are commonly contagious for several days before they show symptoms, the virus can survive on surfaces, and whether it's the situation or biology or something else single infected people have in some cases infected dozens, if not hundreds (the entire South Korean peak apparently can be traced to 1 individual breaking quarantine).
So, a family of 4 goes to a Texas state park and camps for the weekend. Earlier that Friday, one of the parents is exposed and contracts it. They become contagious at some point that weekend while they're still using the toilets, maybe shopping at the store there, whatever. How many people are at the state park on a weekend? For normal business, several hundred, all could be exposed. They won't all come down with it, but chances are good that some people will. Everyone leaves on Sunday, going back to their local places of work for Monday and Tuesday. It is Wednesday of that week before the first person in the chain starts showing symptoms. It then takes 24 hours to get results back on the test, which comes back positive. Meanwhile, anyone who picked it up at the state park is already contagious, most likely without showing any symptoms yet for several days.
How many people need to be tested from this chain? Everyone in the state park has to be tracked down, everyone they work with, their families, everyone at stores they visited. If any of them ran into someone who works at a nursing home, this chain could kill dozens of people shortly. How many people need to be tested to shut down this one chain? Potentially ten thousand. Any one of that chain could be a "Super-spreader" and you don't know which person it is, so you have to track them all down. Furthermore, you don't know how the chain started, so you still have to figure out where the first person got it at. Singapore had enough cases that one person got into a packed facility for migrant workers, and now they have thousands of new cases.
Until we have that little transmission that we can overwhelm every single case with tests, then we're in no position to relax this stuff.