No "people in the club will only vote for others within the club". This is wrong. The club does not take your SP away or prevent you from doing with it what you normally do.

So the club is something you do in addition to you normal curation. The whole point is to allow you to do curation with your steem power, but also capture rewards.

Example: I go around steem reading and upvoting content i like. But then there is steem power left and also I need to capture some of the rewards for myself. The voteclub allows me to capture these rewards without delegating the power away to a voting bot where I straight up sell my voting power.

This way I can actually curate and use my steem power as intended but still get some of the reward benefit.

At the same time it only works if I write posts in the first place.