Oddbean new post about login | logout Everything has tradeoffs. For long term storage, your first two points aren't applicable. 1. You can do it offline and bring your own entropy 2. Most weather can't get through a block of concrete 3. This is valid risk and needs to be mitigated.
Fair point with the key generation. With the single location, I wouldn't be comfy when I need to be. Think about being in 1900 in Europe and trying to find a single secure location where your kids would always be able to access it in time of need for just a next 100 years... Probably more than 95% of land mass or fakilies had some heavy access restrictions put place on them at least for some period during that time. Usually in the most crucial period.