Speaking as a former developer, current designer, I agree that all designers should have some familiarity with the medium they're working in, in addition to the domain they're working in. An industrial designer should learn something about fabrication and manufacturing, and a software designer should learn to code. They don't have to become experts, but ignoring such an enormous aspect of your field for your entire career would be a missed opportunity. I hesitate to call it irresponsible, but to be candid that's personally that's how I view it. Call it an invaluable benefit.