Besides the use of scripts to avoid the kana-only vocabulary, user synonyms may help those who want to focus on kanji.
As example see the image below. Some classical literary works use the kanji version of いつ (see 何時 in the first paragraph of Natsume Soseki’s The Third Night below). And some of kana-only vocabulary may be written in kanji.
I think that only works if you do reviews from your Japanese keyboard? Which I don’t do because it messes up the English input? Not sure, tbh.
In any case this seems like a good solution for people who want to use it as an opportunity to learn more unusual kanji/readings, I could be wrong but I don’t think OP was recommending it as something wanikani itself should do
That’s a good point lol. I’ve had some difficulty in other srs systems with entering kanji instead of hiragana or katakana, I wonder if it actually works in any case