In fact, Russian learners of English often don't see why Indefinite and Continious exist at all, because Russian functions properly without complex grammatical tenses.
Russian can function properly with basically two aspects instead of four (unlike English), but again, those verbs of motion and stuff. =)) In fact, some verbs still make a distinction between simple and continuous aspects, like бегаю/бегу, плаваю/плыву, летаю/лечу, etc.