Why can’t users just use ETH to pay for gas?

VeriDoc Global is a DApp and was never intended for just one single blockchain. Limiting payments to ETH would mean that when VeriDoc Global is available on other blockchains, document issuers would need to pay for fees in multiple cryptocurrencies.

For example, a document issuer wants to create a document hash on the Ethereum, Bitcoin, Stellar Lumens, EOS and Cardano networks. Without a VDG token to cover all the transaction fees across the five networks, the document issuer would need to pay VeriDoc Global using five different cryptocurrencies.