> It's vary rare that a graduating mechanical engineer can weld, for example

Funnily enough, the software engineers from my university (U of Auckland) are all taught how to weld, because all engineering students are (were?) sent to the technical college across the road for a short machine-shop course.

I'd say it was useful for the mechanical engineers and related disciplines, maybe civil engineering, but for most of us it was a bit of a non sequitur (though interesting to some.)