This is VERY common sense. Whenever I heard people talking about how they "wrote their seed in paper and put them in a vault" I laugh. How does that protect you against real life thieves? people in the internet era often forget that real life criminals exist too, and they will try to steal your money. As bitcoin becomes more mainstream, thieves will train themselves to identify how a potential seed looks like. Whenever they see a bunch of incoherent words in a paper they will realize that's an Electrum seed most likely, and then you are fucked, because you either tell them or they may torture you or some other sick stuff.

Honestly, anything that isn't memorizing your password is a risk. And sure, keeping things in your head is a risk too, since you can forget about them, but it sure beats someone finding your seed. Just practice a low. I have lost access to encrypted stuff because I didn't pay enough attention, so I know about that risk myself... but still, I wouldn't feel safe keeping bitcoin stuff around.