Grammar is quite often used to teach students a second language. As far as I know, English speakers in the U.K. and the U.S. aren't taught grammar because by the time they have reached school they've managed to learn the bulk of the language. I believe that at some point in the past educators did teach grammar, but, it appears, in monoglot cultures there's not much advantage to learning grammar. Consequently, the practice was dropped.
I know that German schools teach german grammar, but that's a unique symptom of their heavily gammar-based language and the heavily structured culture.