In an
ideal world we'd have infinite tests (that take 0 seconds to get results) and not need to rely on symptoms that may present differently, or may not even present in some patients. We'd be able to test everyone daily, multiple times, for the virus (nose/throat swab), and for antibodies (blood), and have a system setup for contact tracing. We'd find a way to do that that doesn't infringe on our peace-time civil liberties.
We don't live in an ideal world, unfortunately. In the absence of a Covid-19 test, we could test for the flu, because knowing I have the ordinary flu, or not, vs Covid-19, is still valuable information, especially in places where there is still no ban against large gatherings.
With a few order of magnitudes more testing, whatever the disease, we could go about our normal lives with only slight modifications, rather than this upheaval we're currently undergoing.