Consistency is important, even more so when writing on a modular platform, since the code need to go through a full verification cycle, and bug-fixing relies on these teeming to actually locate bugs and understand how to solve it.
This is why, when writing anything for AdminCore, be it a theme, or a module, you should strive to follow the following guidelines. They are the ones that the AdminCore developers adhere to, and following them is the surest way to have your code be elegantly integrated in AdminCore.
In short, having code consistency helps keeping the code readable and maintainable.
We keep PSR-1 and PSR-12, along with a few nice details from Laravel Core Framework.