What you describe comes across more like versatility. It could be argued either way. You could say its more efficient not to have the T/V distinction because

What you describe comes across more like versatility. It could be argued either way. You could say its more efficient not to have the T/V distinction because then you don't have to think about how you want to express yourself. Conversely, if you wanted to be very polite or very rude, people would have to rely more on context or vocal cues. Thus less efficient because now you have to express the politeness or rudeness in other ways. But in Japanese, you are not only convening politeness information, which can be in the form of polite verbs (Keigo), polite verb endings, and polite pronouns, and honorifics, you are also partially conveying your own perception of your self importance and sense of masculinity or femininity.