The value of the scheme, is that it encouraged people not only to swim, but to get active in other ways as well. I started going swimming with my kids when the scheme was introduced and we now go twice a week, plus a couple of bike rides a week. The two things feed into each other (I also run at least twice or three times a week - I didn't do any of this before I started swimming).
If you do one sport, you tend to do another as you are more motivated - and long term, it saves the country money to have an active, fit, healthy population, rather than a lardy lazy one. Without that one sport, keeping up the other ones would be harder, when you have a running injury you can still swim or cycle, when your shoulders are knackered from swimming, you can still run, when you're sick of cycling you can swim...the more access people have to the more activities, the more likely they are to stay active, and the less they cost the health service, CJ system, SS, etc. I don't think it should necessarily be free, but at a tenner a throw, lots of families will now longer do it weekly and I think that's the minimum you need for it to be a normal, regular part of your life.
I think the other value of the scheme actually, is that it promoted the idea of not sitting on your big fat arse in front of your playstation eating chips, as a Good Thing. It said something about our long term aspirations for our children as a country. Now we're back to playstations, lager and diabetes, which long term, will cost us far more, both culturally and financially. I really wonder why we think we've got the right to host the Olympics, actually.