[steven]

At the risk of taking a lot of slack, I actually agree with Ronin4hire. I have a few reasons for this. I wouldn't say it's like a super "official" writing system, but it is certainly used by most people.

For starters, knowledge of "romaji" is important. It's used for Japanese input on most keyboards, after all. Furthermore it is used on street signs-- above the kanji name of a city, new signs will have romaji. This comes in handy to know how to read the kanji in situations where there are multiple readings. Although this could certainly be done with hiragana, it isn't on a lot of signs. And Japanese people use the "romaji" to be able to read a sign that they aren't familiar with. This is something I've heard come out of the mouths of eldery Japanese and it wasn't like I brought up romaji or anything like that... it just came about in a conversation.

Not that I read too much Japanese, I do notice romaji in different software and hardware manuals.

Sure a lot of people get by without it, but I think there are a lot of people who use it without really thinking about it sometimes.

Although I do admit I agree with why people think it isn't part of Japan's writing system. I just think that because of its prevelance it kind of sneaks in there.