This is a hard one. Totally agree the NHS/Carers come first, with whatever kit is available. However, self preservation kicks in, as with the hoarding, and it is hard to get most people to look beyond themselves/family.
Re how effective are they, hard to be sure, but the evidence from Asian countries where they wear them when they have a cold etc, shows they may be better than nothing. My gut feeling is the fact that these countries were geared up, for such an outbreak, following SARS coupled with their ability to enforce a lockdown, rather than the West's seemingly relaxed attitude, is why the potential impact will be worse here. I just pray i'm wrong.
The bottom line is coping with something like this costs money and the bulk of the population would have thrown their hands up in the air if someone had said before the last election, we will raise income taxes by 2p, to buy lots of equipment which may never be used in case of a potential pandemic. I have seen some articles basically agreeing with the Brazilian president and Sweden to some extent, which is put most crudely survival of the fittest.