I mean, why not, yeah? I don't think that a person needs to live in Japan in order to master Japanese. However, I think that it would be a bit naïve to claim that living in Japan has no benefit whatsoever. Living there, you have such a wide array of study resources everywhere you turn.

Planning a trip to Japan—or, for you more adventurous kids, planning an extended stay in Japan—can be a great motivator for your studying and a great way to reward yourself for all of the hard work that you've done.