It's something that goes toward fulfilling some other requirements, and it is desirable, though I wouldn't make it a requirement.
Indeed, it is not a requirement. It could not be, because there still are plenty of variants that the Interactive Diagram cannot handle.
But I think we could do more to encourage it, in particular by making it more inviting for original contributers to already specify such Diagram (or one from teh Diagram Designer) already in the submisson form, for simple cases. (Which, fortunately, are most cases.) Rather than having to go to some other page, and then copy-paste HTML code that he might not understand. This is why I proposed a 'Computer-Assisted Setup' section in the submission form.
Indeed, it is not a requirement. It could not be, because there still are plenty of variants that the Interactive Diagram cannot handle.
But I think we could do more to encourage it, in particular by making it more inviting for original contributers to already specify such Diagram (or one from teh Diagram Designer) already in the submisson form, for simple cases. (Which, fortunately, are most cases.) Rather than having to go to some other page, and then copy-paste HTML code that he might not understand. This is why I proposed a 'Computer-Assisted Setup' section in the submission form.