I'm wary of not having backups, too. For passkeys to be more than a niche solution, I think the answer for travellers will be not having just your phone, in cas

I'm wary of not having backups, too. For passkeys to be more than a niche solution, I think the answer for travellers will be not having just your phone, in case it breaks. This is a hardware-based solution so there needs to be extra hardware. I have a Yubikey on my keychain and usually have a tablet as well, but it will need to be something more common. To speculate, credit cards have RFID chips in them now, so maybe there is a possibility to identify yourself well enough to buy a phone and restore backups? Meanwhile, if you use Google and Apple password managers, they do have systems to get your password manager back on a new device. For Apple, it seems you need to remember your AppleID password and for Google, the pattern you use to unlock your phone.