While learning grammar can be useful, it should not take up a bulk of students' time because the time could be better spent on more important communication skills. Instead, grammar should be taught only when spare time is found, or even as an elective course.
Studying grammar gives us insight, but doesn't teach communication
We can learn many things about our language and others by learning grammar, but grammar does not teach us how to communicate with one another. Language enthusiasts may find it fascinating, but it is nonessential to students in general.
Understanding our own grammar is essential for learning and adapting to the grammar of other languages. Learning a foreign language's proper sentence structure will help one in forming sentences that are clear and understandable to speakers of said language.