what will google's role be? A bit like paypal?

they can sod off

and any bank which elects to share this bollocks with google. 

Yes, I believe Google's role is to build a more accurate profile about you - they don't just want to know what pron you search for, they also want to know everything about income and spending preferences. 

I'm not sure what benefits (or "benefits") theywill offer to the consumer. Probably an actually usable online banking interface and "cool" cred..