Same problem for any graphical programming environment which doesn't provide proper software tools, like diff's for updates, tests, coverage, debugging. But nevertheless they are used and recommended very successfully.

Matlab Simulink is a very similar environment used professionally to a much higher degree. There are extensions in some toolbox for graphical diffs, but who uses it? Who can review the diffs in a version control system?

And those systems are pretty hard to debug also. In a 10Khz loop you cannot step through or set breakpoints and hardly do printf debugging.