This is one of the most stupid article I began to read (could not read until the end, too painfull).
There is a lot of uses for indexed array access (including, for instance, comparing or using two correlated arrays with only one loop, instead of a nested loop).
Using a function call requires stack manipulation, context switching, etc. Is slow as hell. Thousands of times slow (but don't trust me, do a test, as any scientific method requires).
You are just a bad programmer and hashnode just became a Medium competitor (in article quality).