[mveety]

Why? That's akin to saying a mechanical engineer isn't worth their salt unless they know how to design and implement software. They're two different specialties that do different things. To be a good mechanical engineer you absolutely don't need to be good at making or even have tried to have make software.

[dredmorbius]

Cross-discipline experience is invaluable, especially across several domains. One begins to appreciate commonalities, uniquenesses, and the infuriating significance of details only apparent on in-depth experimentation and iteration.

As with usability testing, small-n samples, say three to five, go a long way.

Do you have cross-domain expertise yourself?

[andrewflnr]

That's all true, and almost entirely irrelevant to the (very strong!) claim "a software engineer who hasn't built some mechanism is not worthy of the title".

[kqr]

But why specifically manufacture of consumer goods, when there are so many other disciplines, like horseback riding, nursing, human resources, and so on.