I think it’s more about getting “real world experience”. Obviously, if you’ve got a “real” job offer, then take it. But for many of us, the chance to work on real projects, get some references, and build our portfolio is a good one. I don’t think future employers are going to look down on it because it was for an NPO. I think they’re going to be more interested in the work that you did and what you learned from it. I think doing an NPO project is more productive than waiting around for a company willing to hire someone with just some fCC certificates and good intentions as credentials.
Just my $.02.