The work of a code is not just to execute a command but to make sure that it can be edited, updated and debugged.
When you first write a code in a language you prefer to write in your comfort level. However, a good code should always adhere to the standards of coding to ensure readability. And maintainability.
There are some particular areas where the members of a team might often have different preferences but will need to agree on something. It's a tough debate about the advantages and disadvantages any system over another. But being consist on a lot of these things have a large impact and advantage rather than being inconsistent: all of the members can read the code and that ensures one part can be used as a reference or standard for another piece of code.
Coding standards are inevitable, and absolutely necessary whether it is being used by Drupal developer for drupal or any other language. These are a set of standard rules, guidelines and methods set for writing every aspect of code followed and maintained by the Drupal community.
These slides tell us about coding standards in general, Drupal coding standards, why they're important and how to implement them. A handy guide for a Drupal developer.