If you're a blind programmer, would you rather listen to a summary of each function in a source file or listen to every token on 10x speed and figure it out yourself? I believe that is the point that they are making. Not sure about the programming while biking though, I typically need to concentrate on one task at a time (which is what most multitasking is realistically, just quickly switching between one task at a time).
Again, what does this have to do with being blind? Whether you can see or not, summaries are nice to have; and whether you can see or not, you still need to read the code in case the summary isn’t accurate, as it typically isn’t
