Research in cognition and language shows that the more children are exposed to language, the more proficient they will become in using language, both their native language and other languages as well. Therefore, the study of a foreign language should start as early as possible in grammar school, as in 3rd grade, and not wait until high school, which is what most schools do.
Because we believe so strongly in teaching Latin, it is the only foreign language we offer. We know students can go on to study language in college or anytime, and their knowledge of Latin will make that easier.
Therefore, the answer to "why study Latin" is: how can we not give our kids this amazing opportunity?