Rapid tests give you a result within 15 minutes. PCR tests you gotta ship to a lab, and wait maybe 2 or 3 days before they report back to you.

I think PCR tests (which nominally take 15 minutes) are the best. But we clearly don't have the infrastructure to support it. Every lab doing PCR tests is going at full throttle and yet we still have this 2 or 3 day delay everywhere.

Meanwhile, at-home rapid tests work immediately. They're way less accurate, but its better to have some degree of testing rather than nothing at all.

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Lets say you have a workforce consisting of 10 people who are sick with COVID19 right now. PCR tests might catch 9/10 of those people. Rapid tests might only catch 6/10.

But removing those 6-people with Rapid tests in your workforce will slow down the spread. 4-people spreading COVID19 in your workplace is better than 10-people spreading COVID19.

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EDIT: More importantly, Rapid tests will catch those 6 people _TODAY_. PCR tests will take ~3 days before they report back, meaning if you're on PCR-tests only, your COVID19 positive people will be around the workforce for 3 days.

If you use both Rapid Tests + PCR tests, you remove those 6 people _TODAY_ from the workforce (meaning 4 people will be spreading COVID19 in your workforce). 3 days later, those 3 other people are removed which is "too late". The Rapid test was in fact more useful.

PCR tests are better for contact tracing, due to their higher reliability. If someone tests positive with PCR tests, you trace their contacts and tell _THOSE_ people to get PCR tests and/or rapid tests, in an attempt to "get ahead" of the disease. (IE: those 3 people who weren't caught by rapid tests were in contact with 15 people total. You now tell those 15 people to rapid test + PCR test).