There’s a ton of words that are commonly or only expressed in hiragana. Foreign words are also common and aren’t really covered by WK either. This course is a decent companion. You won’t get a lot of the context and nuance from just studying them in a vacuum, but I think it’s worth doing for common words. It’s much easier to pick that stuff up from reading later after getting roughly familiar with the terms.
As a side note, there are other decks floating around that I think are a little better, but less convenient than this one. I’ve got a core 6k deck with pictures, context sentences, and audio for every term that makes life a little easier. Dig around the resources list zzzlurg mentioned for more.