Why is in taberu ta written with kanji instead of た
" For writing purposes, we try to use kanji as much as possible. When you read, think of the hiragana as the sounds you make with the letter, and the kanji as the meaning of the letter. If you were to read a paragraph with only hiragana, it could get really tricky, one because there are many words that sound the same but mean different things, and writing with only hiragana would make the paragraph longer than with kanji. Therefore kanji is needed to give your writing a clearer context and make it easier to read. In our case, we wouldn't be wrong if we did say たべる, since there aren't other similar sounding words, but writing out with the kanji, 食べる, makes your writing look more sophisticated in general :)"