That's true, in places MSDE and Express will probably make good systems, more like embedded systems. I still think of production as a system used by multiple people. Too often I've seen people try to showhorn Access or MSDE into a place that it didn't belong and when it grows they wonder why it doesn't perform.

The FAQs for express say that it's an evaluation and testing and learning tool right now. I was leaning more on that informaiton when I was writing.