I came across this video, [Basic Korean Grammar] Most frequent Korean word 이, 그, 저 in my early study of Korean language. At around 5:23, Kim mentioned that "이곳" and "여기" are interchangeble, except that "여기" is a more formal word than "이곳".
I am curious what the difference between these two words is, and if there are any usage notes on using these two words?
The question might be trivial and silly, but thanks in advance anyway.