When I went to earn my TEFL certificate in Prague, I noticed a fun bonus to my language learning experience which put me at a high level (at least for what we were learning) at the linguistic side of teaching.
Linguistics, honestly isn’t important for the learning of a language, but it does play a fun role for how we might understand the language itself. It’s quicker than learning a language so you get a bit of Turpentine effect when learning about languages.
Admittedly, a lot of this has to do with my learning materials. Language transfer teaches a ton of fun little relations from latin between English and Spanish. This gave me a solid etymological sense, nothing near an expert I assume, but it’s interesting to see so many connections which most of us would never even know or consider. You get this feel for the language and can better sense your way through its structures. It can often make you seem like a genius by being able to guess at words that you don’t know and actually hitting the mark.