I think it's a good question, worth asking about *every* dev position being hired for. I would be interested to hear an answer from others on the list. In fact, I think the price of putting a position announcement on Code4lib should be a willingness to answer "why?". And "why not?" is a pretty pathetic answer.
For me, I'm doing what I'm doing because I think it's important and because no one else is doing it. I hope there are many other with a similar answer.