I just now read the last part of this article, as I am in the middle of building an anonymising network and just created the cryptosystem for it.
I am a little amused to read that the hardware wallets are using internal entropy only. Proper strong cryptographic random number sources are fairly expensive, complicated devices and I just can't see a little USB stick and given the prices of these devices having a strong CRNG in them...
It's nice to see that this is being addressed, though. Entropy is a very important resource for secure communication systems. There is a limited supply, and in its absence many attacks exist for weakening encryption and giving away information to attackers, if they can inject predictability into the nonces.