Holy Shiznitz!

Do you know how easy it would be to break an encryption on a file that contained 4 or 8 words from a predefined list???

There are even some algorithms that can guess the words based on size and complexity.
You don't have to decrypt it all, just enough to guess the rest.
And so, there is no encryption at all.

Might as well be sending the bad guys the keys to your wallet.

And you are very correct, with four words known, and at least a bitcoin as the goal, just set a laptop to work on it for a year, maybe not that long. Your only problem is competing crackers.

The biggest problem is your aren't encrypting a big document with all kinds of possibilities.
it is 12 or 24 words from a specific set.

AND!!!! the whole point of having a hardware wallet is that those keys stay in the damn thing and never, ever, ever get exposed to the outside world. Failure at the 0th level there Trezor