[timr]

The value of cheap, ubiquitous antigen testing is that you can be pretty sure that you don't have the virus, which allows scared people to have some sense of control. Even though these tests have a high false-positive rate, it's pretty unlikely that you'll test negative on multiple independent tests, so the cheap and ubiquitous part is important. Scared people can fixate their fear on a metric that actually correlates with transmission. Negative test? No need to freak out about going to the store.

That said, your point is well-taken that people can be idiots about testing positive. We do need to get over this fear and accept that the virus is endemic, and that vaccines work to prevent serious illness. We're now talking about miniscule risks that we would have rightfully shrugged off in any previous year, but folks have been terrorized, and they're desperately looking for control. Any tool that can calm that fear is a good tool.