But if the nurses and doctors are simply taken from elsewhere in the system, they have built a PR exercise more than a hospital, since that does not in itself increase the total care available. And that would not something to be proud of.

It may not provide more carers, but it does have a definite benefit in that staff (doctors/nurses/cleaners etc) are not mixing with two sets of patients, those with Covid19 and those in hospital for other reasons, possibly with weakened immune systems. This avoidance of cross-contamination is very important and shouldn't be belittled.