If i can consider the security of assets with bitcoin i don't think it's advisable to openly publish my seed phrase on the open forum like this, to me it's not safe enough to use the seed phrase in writing a song on a platform like this, someone could easily spy up the keys and further with some actions to aim on attacking the user, there are more secured ways to permanent keep our keys without any compromised, such is in using an encrypted device whereby you can write them and lock the access, or get yourself a hardware wallets if having problem with keeping the keys in a safe way.
But, who says that you will post it here? If you are concerned about the OP, don't worry because I think the seeds that he wrote in the first page is not his personal but it was only an example. Seed phrases shouldn't be posted in public because it was like a password to open up our wallet.
The two ways that you suggested there to secure our keys are great however I only follow one of it at the moment and that is by using an encrypted device. I am using my laptop, usb flash drive and mobile phone. I don't have a hardware wallet for now but I am planning of owning one soon. Apart from these, the op's idea is also cool. I think I will also try it.