I think some see WK as a kanji and vocab source. While it definitely teaches you loads of useful vocab, there are the stories of people using things like 里心 and being told by natives that they should just use ホームシック instead.
Two random anecdotes that spring to mind, though I can’t attribute them to the proper members for the life of me.
One person had to write out the kanji of the words they were using at times for their speaking partners to understand what they meant.
And I believe someone else was called a poet by a native because they used such obscure words for things. (So not all bad!)
That might contribute to the criticism? shrugs
I’m here to learn kanji - I’ll take the mass of useful vocab as a great extra. ^-^
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