By buying votes you deprive others of rewards. It is up to the community to decide what a post is worth and you are making the vote sellers richer.

You will probably still get something from this post, but declining rewards makes it more like buying exposure on Google or elsewhere. Your art is good and you deserve to have more followers, but you should appreciate that we want a better distribution of rewards.

I see you were not commenting much. Reaching out to other artists and art fans is a better way to build your followers. Get more of those and you will earn rewards.