Ouch! For me, looking at the formula I can instantly see what it is, whereas I have to think a bit when I look at the code.
Given how often I've used summations in physics/maths, I shudder at how verbose it would be in code. Something I could write in one line may take up a whole page.
The code on the right is an explanation or implementation you could jump into. The replacement for use would be the function name, such as `summation` or `product`. A computer language is already used to communicate almost all math these days: LaTeX. A slightly lighter syntax, perhaps with optional unicode names, built on a symbolic math package would not be any more cumbersome.
Given how often I've used summations in physics/maths, I shudder at how verbose it would be in code. Something I could write in one line may take up a whole page.