When it comes to audio, most of the above is wrong (or at best, off-base).
Max, PureData and now a new generation of software modular synthesis applications visualize code-that-spews-data-at-other-code. They are used to build highly modifiable (though not dynamic) structures that behave in ways that are often hard to hold in a human mind. They are widely used, much loved, and insanely powerful. They use visualization to add visual memory to the cognitive toolset in ways that textual code does not.
Of course, such tools are unlikely to ever be used build such tools. You don't implement/bootstrap a visual (audio) data flow language using a visual data flow language.
Max, PureData and now a new generation of software modular synthesis applications visualize code-that-spews-data-at-other-code. They are used to build highly modifiable (though not dynamic) structures that behave in ways that are often hard to hold in a human mind. They are widely used, much loved, and insanely powerful. They use visualization to add visual memory to the cognitive toolset in ways that textual code does not.
Of course, such tools are unlikely to ever be used build such tools. You don't implement/bootstrap a visual (audio) data flow language using a visual data flow language.