Earlier quoted context omitted.
You can type it on arbitrary people’s computers, not just your own. Same reason text-editor default shortcuts are important. Not sure about discoverability. Probably they’d just mention the shortcut on the canonical page.
You still need to login in your account then, which can took a significant amount of time especially with 2FA. Then the time gain is so marginal it's insignificant.
But yeah, in general, apps don’t do that much, and I wouldn’t see many being pushed to do so just to add such a shortcut.
Maybe the case here is where the login will be automatic (e.g. OpenID Connect based)? So, in the case where you’d be using some random workstation, but you happen to be authed to it anyway, by e.g. creating a temporary browser profile and logging into the sync on that. But in that case, the browser sync would still give you access to your bookmarks....
Okay, maybe it was never about browser address bars at all. It seems like a lot of these blurbs on the registrar page are talking about how these things are equivalent to certain API calls you can make to these sites. So maybe the point here is to create memorable API endpoints, such that you can now do something like (not saying this works, but it might):
sort -n mydoc.csv | http sheets.new
This would make more sense, because you don’t really have access to your browser’s bookmarks from a terminal; and you might want random agents that you write, which aren’t “logged in” in any particular sense (like a CI bot) to use these shortcuts as well.