Many coins based on ethereum's blockchain one of them DDF, why they choose ethereum because
Ethereum is the fastest growing digital currency in the blockchain market. Each of these cryptocurrencies; bitcoin and Ethereum, are unique. Bitcoin blockchain tracks ownership of digital currency, while Ethereum blockchain operates the programming code of a decentralized application. This difference leads to huge implications. Instead of being restricted to a single use, Ethereum is used for creating unlimited distributed applications.
DDF believes that Ethereum ICOs are innovative and democratic funding processes, as they generate new crypto tokens and enable their exchange with Ether
https://bitcointalk.org/index.php?topic=1992157.0That is topic about DDF for detail information.