I believe mobile devices will replace traditional wallet including cash, loyalty cards, ticketing card for public transportation and so on.  One tool can be used for many purposes with same user experience.

• Are you ready for use mobile phone to do payments when it is possible?
• What are the most relevant situations where you want to use mobile phone for payments?
  

I think that Single Sign-On authentication with mobile phone can increase user experience in new level really. Same PIN for every ser..