Fiat seems to work fine for what ShareRing is trying to accomplish, why does ShareToken need a Blockchain?

Fiat seems to work fine for what ShareRing is trying to accomplish, why does ShareToken need a Blockchain?

 Fiat works fine when you’re paying for a sharing economy service in your local currency, but as soon as you travel overseas and wish to use services in other countries, you’re dealing with FX fees and currency exchanges. Or, even worse, you can’t even use an overseas credit card.  Furthermore, by using ShareRing, you have 1 login for any sharing economy service, anywhere. You can also earn SharePay by renting out your own things through a ShareRing provider, and then use that SharePay to pay for a sharing service with another provider somewhere else in the world, all with one app.