tooling tends to suck, input ends up being slower once you know how to do it. (Argument to be made that visual is faster on a tablet with no keyboard. Okay).

You still have to type to name things.

Density of stuff on the screen is lower.

Not sure about readability (you can find readability advantages for any format if you ask the right person). I would bet math expressions with many terms are clearer in a visual format like tex.

Visual elides the connection between functions and files/modules, potentially making it hard to scale projects.