no, it isn't.
what is essential to understanding the construction of english, is for students to pay the eff attention to what they're being taught in english.
That's what's important to score well on tests- which is all that's important to most, sure.
True comprehension of structure and construction of your language is something that requires complete abstraction it seems, at least this has been my own experience and the experience of pretty much everyone I've ever talked to about the subject.
I never 'really' understood some pretty basic concepts of English... I mean, yeah, I could pick out things like objects, infinitives, clauses... but actually understanding what they were, how an entire sentence, and each of its bits, functions as an expression of thought never occurred to me until I started learning German (and, as I've said before, this is a common observation among pretty much everyone I've ever spoken to). And, due to the policies of my school district (which are pretty much similar to schools all around the country), this didn't come until the 8th grade.
Every child should learn a foreign language from an early age, just for the sake of mental exercise. I don't particularly like Spanish either, which is why I still don't know any, but the fact of the matter is that Spanish is a natural choice for this, for several reasons: obviously, Spanish is a Romance language, so vocabulary and to a lesser extent grammatical structure is already fairly familiar, or should be made familiar as over half of English is based on Latin & Romanic roots)- Spanish, being a Romance language, also sets you up for other Romance languages you may want to learn out of your own interest, whether that be French, Italian, Latin, etc.. But, in the end, what puts Spanish above Danish or French or German (to say nothing of Latin), is that living in the United States, like it or not, you have more opportunities to speak Spanish with native speakers than any other language beside English... it's easier to practice and, again, like it or not, has more practical application... Which is important if you'd really like to make it something more than a mental exercise.