It's great that Mozilla has made Persona open for everyone to develop with. While I still believe that Firefox has a lot to gain with Persona, I also agree with your vision that this is a good step towards a safer web (only time will tell if this takes off). I'll take it a step further and argue that if Firefox lead the charge with Persona tightly integrated, it'll make the web even SAFER for the average user, because it will force other browsers to tackle the issue of security as well, benefiting all users regardless of browser platform.