I'm not in favour. The only decent argument would be if the NHS was becoming so overwhelmed that other important procedures couldn't carry on. (In some regions they might be getting close to that point, but I'd back local lockdown for that, not national).
The average age of those who have died from coronavirus in England and Wales since the start of the pandemic is 82.4 years old. Whilst it might seem a bit callous, I don't think that's totally insignificant when considering how much to knacker the economy.