Hi @vipnata how do you do? I think it is because this dapps giving the service of auto-upvote by following specific users upvote and also we may auto-upvote our favorite author too. Also the owner is top Steem Witness, so we kind of trust him. Unfortunately it cannot be trusted now since some of their users get their funds stolen after giving out their active key in order to use this dapps. If I remember correctly, we only need posting key to use this service back then, but now they require our active key too.