[rdtsc]

There is readable based on each character such as semicolons, dots or curly braces and there is readable based on the shape of code.

That is two separate levels. When you first glance a page of code the first time in 1 second, you should tell what the structure of the program is. How many blocks (for/while/if) it has. How many functions, how big they. You haven't yet had time to read each individual character. That is one level.

Here variable and ambiguous indentation rules get in the way. If there is non-uniform, non-standard indentation then you have to start reading individual lines in detail. If there is standard indentation then it doesn't even matter about little commas and semicolons, it is a level higher than that.

Then past that it is about individual functions, classes, modules, and what have you. Then it becomes about == vs = or . vs , and so on. If there is ambiguity there it could be harder. Like in Python I added a , at the end of a some variable. So that turns it into a tuple. And it resulted in a strange exception down the line. In C the = vs == is notorious. But there are others. None of this make the task impossible, but just slightly harder. The problem is that if this is done many many time over the course of a lifetime of a piece of code. Maybe it take 10 extra seconds for reader to understand the code, that multiplied by thousands of times will add up.