It's an interesting article and experiment, but there are certainly some pretty big flaws in his arguments.
If, for example, someone received today a floppy disk or a Sony minidisk from the ’90s, it would be very hard to find a device able to read it now.
This is nonsense. With Amazon Prime and 10 bucks, I can have a floppy disk drive delivered to my door within 24 hours. With a car and a local computer store, I can get one within the hour. And this is a technology with is 50 years old and from a time when some houses had a single computer, maybe. We now live in time where every person, let alone every house, has multiple devices using USB - computers and all their peripherals, TVs, games consoles and peripherals, mobile phones, chargers, power banks, cars, etc. There is no way you are going to have any problem using a USB device in 20 years' time.
possibly requiring the beneficiary to derive manually from the seed in order to find the keys where the coins are
Again, although wallets may move on from BIP44 or BIP84, support for these will always exist. There is no way in 20 years people will have to manually derive these keys. There are far too many sites, repositories, programs, etc. out there. Only a complete failure of the internet would make every single one of these inaccessible.
If storing coins for 20 years I would also choose something like steel engraving, but rather because I wouldn't want to trust that the digital hardware wasn't going to degrade in that time rather than the reasons above.
Hello, the author of the article here. I agree that there will always be a way in the future to use past technology, surely you. can buy all the necessary adapters on Amazon and find some software to derived an HD seed with an out of fashion standard, but one of my design goals was to keep things simple. Today it would be annoying and time consuming to buy a floppy disk reader for a single use, and in the future it could be even worst: it's not hard to imagine a future were teenagers are totally foreign to the idea of physically connect an external storage to their device, as wireless and cloud alternatives become more popular. Obviously I may be wrong on this, the truth is that we just cannot know how consumer grade technology will evolve, so avoiding electronic devices all together seemed like the safest option to keep the redeem phase simple.
Moreover writing down a key on a physical support is just more reliable for long term storage than any digital storage medium.
