It almost makes me wonder if STB isn't an accident, because some sort of research shows that cancer like that somehow causes sales increases.
They've actually talked about this some. The card used to be even more OP if you can believe that. They nerfed it late in the process and actually assumed it would be fine where it is now, and they said they didn't necessary have time to fully playtest the current version.
http://www.ign.com/articles/2017/01/12/hearthstone-small-time-buccaneer-has-already-been-nerfed