Firstly "unhackable" in the marketing makes me trust it less. Everything is hackable.
I am not sure what the threat vector is that makes this more secure than hashing a password in a single database.
With hashing the server doesn't know your password. If you picked a poor password a hacker with the hash could guess it I suppose but you can mitigate against that.
Also if someone can hack into server A, however they did that is likely to work for B unless they are managed on different clouds by different teams and share no common code or prod access.
I am not sure what the threat vector is that makes this more secure than hashing a password in a single database.
With hashing the server doesn't know your password. If you picked a poor password a hacker with the hash could guess it I suppose but you can mitigate against that.
Also if someone can hack into server A, however they did that is likely to work for B unless they are managed on different clouds by different teams and share no common code or prod access.