FWIW, I've found that the -v flag often doesn't say why it's not using your key, just that it isn't using your key and it has fallen back to password authentication.
It's usually not terribly helpful for figuring out why it's not using your key, just that it's not using your key, which you kind of already know if it's prompting you for a password. lol
Ooh, then your mouse can stop working when you run out of meters and then you have to buy more to top it up! Excellent.