I think it's a good idea. Why to restrict the rewards only to posting and curating ? If there is no rewards, there is no good reason for minnows to vote for a witness, especially if they don't have the technical knowledge to judge all witness. So what is preventing our witnesses to offer some good rewards for voting them. Consider it as a giveback to the community. Minnows will appreciate it. They are struggling to get noticed here. @isnochys and @steemhq.witness are already offering rewards for giving them witness vote. So I have given my votes to them. Hope I will get some rewards. May be very less. But I liked there idea. So I will support those who follow there path of giving rewards to witness vote. Ultimately all witnesses will have to follow there path. Because it's a great way to indirectly take part in steem mining. Promoting this idea will indirectly help the steem blockchain. Steem witnesses have to get maximum producer rewards to offer a competitive reward rate back to the people who vote for them. This will force them to avoid missing any blocks. So this idea is beneficial not only to the wittness and those who vote for them. It's beneficial to the entire steem blockchain.