Can we use DigiByte in a system similar to ethereum so that DigiByte is used as a fuel (gas, payment) to do smart contract? Maybe it is not necessary as that market is occupied by Ethereum already.
Who would want to?
But seriously, have you really researched Ethereum? Their code base? Their network security? Their total lack of scaleability? Their distribution? Their pre-mine? Their now current cost cuttings with office closures? Well, I do admit they are good at marketing and packaging, but if that's all they've got, would you really want to imitate them? Ethereum?
They're light years behind us.