I have ParmAirGaps available worldwide - Dismembered Thinkpad Laptops without WiFi or BlueTooth cards, Electrum & Sparrow Wallets installed, and a webcam for QR signing transactions, fully encrypted. Let me tell you what they are for...

1) Make seeds

You can use it to verify checksums of bespoke seeds that you roll yourself - I have guides for that.

2) Verify the honesty of HWWs

You can use it to verify the addresses of wallets made by hardware wallets. How do you know they are not using parallel seeds and pretending to use the seed you created or entered? Even if you use some dice roll feature, you can't know if the addresses truly belong to the seed you think you're using. Even if you have a passphrase, this risk exists. If you're paranoid enough, you can enter the seed into the ParmAirGap's Electrum/Sparrow wallet (don't use a regular computer, that's bloody dangerous), then check that the addresses generated are the same as the ones from the hardware wallet. Then you're good, and you can delete the ParmAirGap wallet you just created (if you want).

3) Storage & Encryption

It's up to you if you want to use the device as a stateless machine (store keys on it or not). It is safe because the drive is encrypted. Air-gapped computers with encrypted drives are still vulnerable because an attacker can remove the drive and attach it to their computer, then explore the file system without needing to enter a password. In addition to the drive being encrypted, you can encrypt any wallet files

you create - the software offers that. Even if you forget the password, you've learned from Parman and you know to have backup redundancy.

4) Inheritance

On this computer it is safe to generate letters with high detail about bitcoin recovery. You can then encrypt the file and put it on a USB device. Ideally, put it on a Tails USB drive. Available on request, or make your own. To get assistance with inheritance planning, BetterCallParman (TM).

5) Signing

It can be used as a signing device - partially signed transactions can be passed around by QR code for extra safety. Even safer is to have multiple devices geographically separated with each device only ever having knowledge of one key. Then you pass the transaction around until it is fully signed. BetterCallParman to learn how (mentorship or individual lesson).

6) Uncle Jim like a champ.

With one of these it's easy to create keys for your family, and even store and encrypt keys for them as their backup.

FUD

Note that there is FUD going around that these can be hacked, but c'mon, these are laboratory condition attacks AND at the very least the device needs to be tampered by an attacker and then put back without you noticing. If it truly is a concern, get 2 or 3 of them and do multisig.

You can get one here...