Seriously, what's up with katakana? Are katakana really necessary?
Kanji, I can understand, because they have meanings, they look cool, they're compact.
Hiragana, well... they're a super-simplified, purely phonetic version of kanji script. OK, that's useful.
But katakana?
You see, the only purpose of katakana is to save face. Without them, any gaijin looking over your shoulder could immediately see that you spell "beer" as "biiru" and "golf" as "gorufu" and start laughing at you. But with katakana, now you can just pretend that a better spelling is impossible! "It's not me, it's the writing system!"