Yes, it's true that reading and writing at an adult level requires knowing at least the "common" ones, about two to three thousand Kanji characters. However, H

Yes, it's true that reading and writing at an adult level requires knowing at least the "common" ones, about two to three thousand Kanji characters. However, Hiragana and Katakana are not just for children or students. They form a significant portion of everyday text, and in fact necessary for constructing sentences properly in Japanese. For example, many/most grammatical particles like "of", "in", "to", "from", are written in Hiragana. And foreign/imported words are usually in Katakana. Regarding the ease of pronunciation - I think the grandparent comment was talking about the sounds of the language, not about memorizing how to read and pronounce the text. Japanese speech is composed of a fairly small set of simple sounds, similar to Spanish. Having taught both Japanese and English, I would say the latter has many more tricky sounds - like th in "the", or ar in arm (especially how Americans say it). In contrast, if one knows the sounds of each Hiragana (consonant + vowel combination), they cover almost all of Japanese speech.