Wow! Thank you for your support.
Regarding the signing and destroying, its purpose is to cryptographic sign messages offline.
Once that message is signed, transfer it via camera imaging (qr code) to a online machine so that it can be broadcast.
Similar purpose as trezor and ledger .
Even if you use "shred" command, information is still recoverable via forensics, hence destroy a $5 sd drive.
All "Cloak and Dagger" stuff.
I just experiment and have fun.