Reading the text on their indiegogo page, they accuse other wallets of a lot of negative things, but offer absolutely zero proof that they don't do the same thing. An example:
Existing solutions give you a key, so they may have a database holding all the keys they ever made, including yours. They also rely completely on the interior chip for generating your key, and also here there could be backdoors, as has been proven in recent history.
The ZERO introduces a whole new key generation process that not only relies on the interior chip, but that also includes your biometrics and your surrounding light.
That's great and all, but there is absolutely zero proof that they also don't just "give you a key". You can scan my fingerprint, you can even let me enter my own entropy, and then just spit out a pre-generated key anyway. Unless I am generating my key manually by flipping a coin or similar, then I am still "relying completely on the interior chip".
A couple of other concerning things:
The NGRAVE "Perfect Key" is the 64 character hexadecimal equivalent of a 24-word mnemonic phrase / 256-bit (0s and 1s) master seed. Hexadecimal means that each character of the key can have one of 16 values (0-9; A-F). With 16 values per character and 64 characters, this equals a 256 bit key. What makes the “perfect key” is the ability to resolve the challenges of using words-based backups.
Why are they encouraging people to back up a 64 digit hexadecimal number?
As the ZERO never needs to connect over USB, Bluetooth, NFC, Wifi, 4G or any other network connection, hackers simply cannot even attempt to steal your crypto.
That's all well and good, except:
There is a USB-C port for charging and firmware updates.
So there absolutely is a USB connection that hackers could exploit.
It looks nice, I'll give them that, but so far it is just another airgapped device you communicate with using QR codes. Until it has been aggressively penetration tested, then it certainly isn't worth $250.