If you do not follow these rules, it will turn out that one function in the code will be written in one style, and the second in another. This will simply be difficult to read. It’s like with a book. Imagine that you are reading a book with good content, but half of its page is in Times new roman 14, and half is in comic sans 16, also with chaotic italics and mismatched capitals. It seems that you can read it, the meaning is not lost. It's the same with the code. It will work, but a residue will remain.

If it’s very basic, then we can distinguish three levels of code beauty:

1. Visual. This is all about coding conventions, correct variables, design, etc.
2. Perception of the code. About the feelings that people have when working with your code.
3. Thoughtful architecture. This is also critical and also relates specifically to the beauty of the code.

Let's be clear up front that we're discussing code that does the job it's supposed to do, and does it right. It makes no sense to evaluate non-working code from the point of view of beauty.