Text might be good for programming because, most of the programming are sequential, text is sequential, and text processing is highly optimized in the brain because language. But in fact, we also use a bit of visual programming (indentation, paragraphs) in text to reflect part of the program structure that are not sequential.
If the program is completely non-sequential, visual tools which reflects the structure of the program are going to be much better than text. For example, if you are designing a electronic circuit, you draw a circuit diagram. Describing a electronic circuit purely in text is not going to be very helpful.