There’s plenty of ways to cheat, for a start. Which could be tempting to do if one’s goal was to hit 60 before the subscription runs out.
Now people will tell you that WK isn’t a vocab tool, which it isn’t, there’s still a lot of value learning a lot of the vocabulary available but using a reordering script, you could just skip every single bit of it.
The main thing I mean is that you near-instantly recall the reading and meaning of the word in Japanese. The idea of mnenomics and an SRS is that the first few recalls, you’re just doing pattern recognition. You break the kanji down into it’s radicals, recall the mnemonic, and then from there you derive the meaning in English. As you do more recalls, the links in the brain start to move the kanji into a learned thing, you no longer break up into radicals, or recall mnemonics, and ultimately don’t translate into English. You just understand that kanji is read x and means y.
It’s very easy, in comparison, to do the first thing but you don’t actually know the kanji at that point. You know how to decipher the kanji but you don’t know it. Only with repeated correct SRS recalls and ultimately reading the kanji in native material will you truly learn them. I can’t do that if I rushed through it.
As a very simple example, 犬 is a kanji I knew before I started WK. I’ve encountered it so much in textbooks, and on forum posts here, and obviously have reviewed it lots of times in WK that I don’t go oh that’s that kanji, it means dog, etc etc. I immediately read いぬ and can visualise a little 4 legged companion. I can think of 犬 in Japanese.
However, a recent kanji I’ve learned is 信, but I haven’t learned it well (yet!). The radicals are leader and say, what should you do with what the leader says? Believe him of course! If you don’t believe him, he’ll kick you in the しん! (not the official mnemonic from WK but it works for me) So while I can parse this kanji, if I encountered it in the wild, I’d have to break it down into the mnemonic and translate it. I know the kanji but I haven’t learned or understood it.
I hope this makes sense.