The $DGT will be an ERC20 token during the DeFi liquidity pool campaign, you are correct in the fact that he native $DGT token will be its own code and NOT ERC20. There will be a conversion from the DGT-ERC token to the Native $DGT upon launch of Mainnet.
We do not and will not support Smart Contracts on the DataGrid Blockchain, that is sooooo 2018. We have upgraded the old stale static and non scalable Blockchain to an Object Oriented Blockchain with a Decentralized GlobalOS. This allows developers to create apps and users to participate in the ecosystem without having to know anything about the underlying technology.
The diference between the two tokens, $ETH is a Store of Value (another digital gold) and the $DGT is a global stabilized currency based on the internal blockchain economy.