Personally, I'm glad to see this development. I'm biased because I'm a classical musician and have worked for a professional orchestra, but I also can't see this affecting any more than a handful of jobs (literally, count them with your two hands).
I worked for an orchestra that had to leave a position unfulfilled for a few years simply because they couldn't find a single American player they liked. It was even more complicated due to union regulations of the audition process itself -- screened tapings and blind auditions, so that the judges don't know the identity of the applicant until he's already been hired as the winner. It all really boiled down to the fact that they desired a different type of playing from what was being taught in American conservatories. The arts is truly international -- it prospers with the exchange of cultures and backgrounds.
Is their contribution more important than social workers? Well, they certainly won't bring the country out of "recession", but I think it really depends on your position of art's role in the community. I think that most would agree that the UK's cultural climate helps to contribute to it being such a desirable place to visit (and live). If you don't agree, then I'd ask you to picture a place like London without the theatre, orchestra, opera, clubs, etc, even during a recession. Sure, it doesn't affect your life every single day, but it's still a big part of the appeal.
Musicians needed, but no announced shortage of vocalists anywhere in sight. That's quite probably because there's an over abundance of 'falsetto's' in the government already... 
It's not quite the same because orchestral musicians can actually be employed in full-time, permanent positions. Vocalists are only contracted per gig. I know of very few permanent positions, except perhaps the US Army and maybe the National Chorale.
