Smartsteem is a service where it uses your votes, and pays you for them. ROI is a ​return on investment. so if i invest 10Steem with a bot that has 10%ROI i should get 11Steem. And i delegate to smartsteem to use my votes while I'm​ away or busy at work and don't have time to use them and i delegate to smart-ua because i believe in the project!