"Using" a programming language is 99% reading and understanding code and 1% writing code. I only control the 1% i write and not the 99% I read. You can't know

"Using" a programming language is 99% reading and understanding code and 1% writing code. I only control the 1% i write and not the 99% I read. You can't know everything but you need to know enough to understand most of the code you read. If a feature becomes popular among others, then you need to understand it, even if you never use it yourself.