I like the Power Ranking. I hope it stays. I like the reader direct interaction with the Ranking Chart.
In China, the Monthly Ticket Ranking is the most popular chart on Qidian. IIRC, every $2.5 worth of purchase on Qidian get 1 monthly ticket which give incentive to readers to spend money there. The more money spend, the more the authors earn since Qidian pays 70% royalties.
It is also a good discovery tool to see which novel is popular with fans.