The thing is, a working testing system for contacts of positive people is absolutely the right way forward. Anybody arguing differently is just doing it because it's a new idea from the government.
The issue is, they literally made it up to try and get Johnson and Sunak out of isolation and that was blatantly obvious.
But as an idea, it's entirely sensible.
People who count as close contacts, have that initial period of isolation but again, base it on PCRs.
So, 24 hours (still crap but as
@PhilM said, not as crap) and then perhaps have to then have a follow up PCR if you're negative the next day.
PCRs are meant to be the accurate ones, so have them used in this instance.
If you test positive on the first PCR, then you have to isolate but again, have interval tests through the period of isolation to get you out.