The most obvious reason natural language is a poor choice for programming is ambiguity.

Time flies like an arrow.

I saw the parade coming through the window.

For small programs that basically duplicate something else with a few tweaks, sure, natural language can be fine. "The same thing as A, but with a red border, and add a new button to do X." Beyond that things start to get tricky.

Interactive programming has far more value than natural language programming, and agents also give you that. An ambiguous natural language spec. that leads to the wrong result is less problematic when you can interactively correct the problem; "No, that button should have been on the left hand side." It is the new version of REPL.