I think it's a question of sharpening research skills. It's a qualitative deepening of critical thinking, and the step far beyond passable or great to great and original.

I think it's a bit like comparing high school math with university math. Or like saying that you can program after taking a single programing course. :)

Similar skills can be gained elsewhere, are other skill sets are often needed in industry.

I have to agree with the rest - do a PhD if you clearly want to do research/work in academia. If you're just doing it for the credentials - stay far,far away. You might survive, but you will be utterly miserable.