You can take a look at this thread to see what kind of word are fairly obscure but pop up from time to time and thus would appear in those > 60 levels. Basically tons of words using unique kanji that appear only in a few words.
It would be quite a waste of time to learn them following WK formula, spending time and effort learning several individual kanji and their reading, only to be used in only one word.
Actually, there is already one vocab like this in WK. At some point we learn 挨 “push open” with and 拶 “draw close”, only to learn one single word 挨拶 which mean greeting. It’s arguably an important vocab but by learning it WK style, it means spending lot of effort trying to keep in mind the “push open” or “draw close” meaning, reciting mnemonics, maybe fail those card from time to time etc. All of this quite useless because 挨 and 拶 are never used anywhere else but in 挨拶.