[vorg]

Katakata, like zhuyin, is "hanzi/kanji written small", just as hiragana is "hanzi written quickly". I see hanzi/kanji, katakana, and zhuyin (but not hiragana) as all part of the same "alphabet" used to build up hanzi recursively. Many katakana are components of hanzi.

[erjiang]

Maybe, but this is rather like using a Cyrillic letter in a Spanish-teaching website. "What language are you teaching anyways?"