Why go through all that trouble when you can secure it with something that is more secure and convenient and costs only 89?
The reason is to have 100% control (you aren't relying on any 3rd-party for salvation).
The method I suggested is not less secure and is not troublesome for the sake of 100% control, max security, and cost far less.
But then, to each his own (for those who seek the easiest way out for max convenience regardless of less control may get the hardware wallet).
Even then using hardware wallet does not spare the user the trouble of securing the mnemonic phrases.
However, I dislike the video implying .rar file is insecure, that everyone needs to have Trezor, and that to me is false information.
Mike B could have educated the viewers on how to make a very secure cold storage in .rar with strong encryption instead, but he didn't.
In fact, I dislike (and never recommend) using hardware wallet also because if something screws up (such as the mnemonic phrases got lost or stolen), the whole savings is at stake.
With my method, savings can be segregated into multiple addresses and compartmentalized in varying level of security as the user prefers, and any address at stake will not jeopardize the others.
Nevertheless, to each his own.
I do not wish to impair nor harm anyone with my suggestion nor wish to be penalized for making a good suggestion.