Are you suggesting they are likely beneficial but our government lie, so that more may be available to medics, while if they had been conscientious and proactive they would have stockpiled them en-masse cheaply beforehand?
Think masks/respirators of all kinds were sold out in shops, at regular prices that is, about two weeks ago in UK. I wouldn't be surprised if practically all are imported.
I've not read the government's nudge unit or behavioural stuff that other people have put up. It isn't just the UK that's had this problem. I don't have the stomach to read all the stuff coming out of Washington State or California these days, but it looks like other countries have problems. I've no idea why there are quite so many masks (where mask is a generic word for mask and respirator) in Italy, but there are.
I do think in general that yes a lot of government's policy is motivated from not getting people to panic.
Masks and respirators are highly beneficial to medics and probably for other staff interacting with the public such as pharmacies, shops and for patients who have the virus. 8.3% of all positive cases are medics in Italy. They help get the infection rate down outside the home (or within if people were wearing them inside) which all adds up.
I work from the assumption that there aren't enough in the UK for mass wearing, so what's the best use of them? If they weren't in short supply, yes people would be wearing them routinely when going out. Well I said would...
Speaking generally in Italy, schools were closed early on, masks worn by high percentage of the population. It's not clear at all and to be determined by others that these two measures were particularly effective regrettably.
I also think people don't play a blind bit of notice to what people say and I have no idea why you think they do, again citing Italy as an example - it took 5 bites of the cherry. People are laughing at Boris with let's call it two sets of soft measures so far and closures today. Even Germany which I know a lot less about seems to be getting annoyed and saying Monday it's more measures if this doesn't work.