> every time I sign up to a site I need to grab all 5+ devices I might ever use and add them to every site, or I can't e.g. log into my D&D game while travelling because I forgot to generate a key on the work laptop?
You don't need to log in to every app on every device the instant you register a new account. Just make a passkey on a couple of devices that you're likely to have around and you'll probably have what you need when you need it. When I register on a new site that uses passkeys, I might create a key on whatever computer I'm on and a portable authenticator like my phone or my security token.
So, say I'm at home on my deskop, and TotallyCoolService has the option for a passkey. I'll make one on my desktop, and then go ahead and make one on my security token. Later I'm out and I want to check in on TotallyCoolService on my phone. No worries, I just tap my security token to my phone and I'm logged in. Later I'm in the garage working on my motorcycle and want to reference something on TotallyCoolService on my laptop and my USB token is in my backpack inside. No problem, I can sign in with my phone. Now I've got security tokens on most of my common devices and its not like I had to spend time gathering all of them at account creation.
I don't instantly run home to my desktop and log in the moment I sign up for a new site while out and about. But I do go and sign in eventually, even if only to ensure there's a backup key there.
