Be frank, aren't there some long poems that you learned so well in school that you still remember them word by word?
If yes, then I hope you got my point.
Of course. But
as I pointed out in an older post which was quoted earlier in this thread, I am under no illusion that I could very easily forget such things through no fault of my own and with absolutely no warning. Anyone can have a stroke at any time. Anyone can simply trip and hit their head on the sidewalk at any time. Anyone can contract meningitis at any time. The number of possible ways your memory can be damaged cannot be counted. I don't like those odds, especially when it is so trivially easy to overcome them by simply writing your seed phrase on a piece of paper.
what makes you confident in remembering the secret place where you stored your keys?
If I forget, I'll ask my wife. And as I said above, I can at least look for a physical back up in places I am likely to store one. If you forget your seed phrase, then you are shit outta luck.