It makes sense to change credentials periodically, but the policy of 30 days for humans doesn't work because the humans aren't realistically going to remember new credentials every 30 days.
If you have Let's Encrypt, the default setup (Certbot) will change the key every time it renews, typically 60 days, but you aren't expected to remember the key it's just data for a machine to store somewhere, so there's no practical problem and it defuses some risks (e.g. bad guys get hold of old backups). So the idea of rotating credentials like this would make sense _if humans weren't expected to remember them_.
It would be a significant time investment to be checked out in a radically different type like this, but not impossible. It mostly comes down to the systems, avionics, and procedures which can be radically different already, even in similar-looking planes.
I also wonder about engine placement. Engines on top will push the nose downwards in case of adding more trust. There is also issue of stalling on ascend. On ascend, wings would very easily obstruct air going into engines, reducing their power. Also currently aft-mounted engines require vertical stabilizer to be above them to counter act the forces generated by the engines. I don't see any vertical stabilizers in this concept.
I completely agree but the consideration is your phone is dead and you need to get ahold of someone. You should be able to easily memorize some way to contact emergency contacts IMO.
