From Slackjore who writes the Byteball Wiki:

The thing is you're only giving your details to ONE entity, Jumio. Other entities you give them the fact that you're attested, and whatever else is the minimum they need. It's a bit like PayPal has your credit card info, but when you buy something from a random company they don't get your cc info, just that PayPal attests you're ok. Jumio doesn't even know your Byteball address.