The standard private chains will require Stratis tokens to be 'locked' as part of the 2 way peg to private chains. Stratis tokens will also be the currency utilized to pay transaction fees to miners. When we migrate to POS Stratis tokens will be used to secure the Stratis chain and the private chains.The Blockchain-as-a-Service platform will be also be fueled by Stratis tokens, users will be able to deposit digital currencies or pay via paypal and Fiat to 'credit' their account with Stratis tokens to fuel their node.Our fiat gateway technology will also charge a fee in Stratis, but note there will most likely be a fee on the fiat side also. This will be one of the centralized components of the Stratis Platform, but its the only way to have Fiat gateways and be compliant with the various regulations involved.

Whitepaper: http://stratisplatform.com/files/Stratis_Whitepaper.pdf