I have this device and use it to store my keepassxc and onlykey backups, and it’s useful to me because I’ve stopped using passwords (I only need to remember the pins for these devices which can unlock my keepass dbs that have everything else).
It seems secure enough for my use case, especially since the files I store in it are themselves encrypted (the onlykey backup still requires a pin), but I still want them to be difficult to access.
I’ve had to rely on it before but only because I didn’t prepare a backup onlykey ahead of time- ideally it should be one of many recovery methods. But so far it’s worked great for me.
I suppose the most tangible benefit I get out of it is embedding a custom initramfs into the kernel and using it as an EFI stub. And I usually disable module loading and compile in everything I need, which feels cleaner. Also I make sure to tune the settings for my CPU and GPU, enable various virtualization options, and force SELinux to always remain active, among other things.