It didn't really make any sense to me, either. The doc didn't explain, just said there were "alternatives" -- like putting me on birth control pills, which I don't like taking due to side effects. It doesn't make sense, especially when you consider a surgeon could probably do a dozen vasectomies in a day! I don't know when it would be a priority, either. Maybe for someone who already had several children (we don't have any and would like to keep it that way).
It's a bit of a crock, as the taxes we pay here are basically like paying for medical insurance. And in the states, many insurance companies would cover a vasectomy. Here, you pay for the services but then get denied them (as was the case when I needed to see a specialist for my knees and just had to do that on my private insurance as the doc told me it was basically not worth it to even try to see one on the NHS). My husband isn't on private insurance, though, so no vasectomy until we can get back to the States and get covered by real insurance again. (and it's not like my private insurance from the states is working well here -- they're confused as hell by the fact that I live in the UK and haven't been paying me back, but that's another story.)