The key to good English spelling is the meticulous study of etymology; I learned this when I was about five years of age. Once you get used to thinking about words in terms of their root languages, then things start to make sense most of the time, except for all the exceptions.
I'd argue it's the key to good understanding and use of any language
They're not talking about that, they're saying "We can't remember how the word looks at all". It's pretty neat as a problem to have, to be able to say it but not even have an idea about how it might be spelled.
FWIW, I could write it correctly, but I also spend 40 minutes per day practicing vocabulary, the bulk of which is spent on writing the characters.
I can guarantee you that each of those students would recognise the character if they saw it, they just can't generate it correctly from scratch.