When you don't start with music theory (which took many centuries to develop) you end up with lots of things that work but not as well.

You don't have to learn music theory yourself, so long as theory is something someone knew in the past to design how you learn. What matters is that you learn the useful patterns, why those patterns are useful is not something you need to know (except if you are trying to break the rules - understanding the rules means you understand what happens when you break them and thus can come up with good breakages instead of unmusical noise)