[jancsika]

So in terms of git, Luna users won't be able to comprehend the visual z-order and positional changes by glancing at a diff. And those types of changes will come freely in the normal course of development.

That means that Luna requires some kind of visual diffing step to reach parity with the development flow of text-based languages. Otherwise developers will get comfortable interpreting metadata changes as noise. In specialized languages like Max/MSP that leads to spaghetti programs. In more general visual languages it could probably even lead to security issues if an overlap suggest a different visual data flow than the source code. (And judging by Pharmaceutical TV commercials, people blithely favor the visual over the written when there's a discrepancy.)