A Disney type system would be useless? As sharp and succesfull as Disney parks are you think that they did something that was useless to them from a business standpoint? BOTH systems create revenue and value for the parks. Disney creates value by increasing and bettering the guest experience at no cost to the guest. This promotes return visits, loyalty, image, etc. Their system also allows the guests to do other things besides stand in line . . . like play games, eat or shop or ride other rides. At the and of the day it is VERY DIFFICULT to know how much extra revenue the park realizes because of these intangible, hard to measure benefits. Most guests love it, few complain about it.
Kings Island's system simply increases their revenue. At the end of the day they pretty much know how much money they made off of it. Some of the other things come into play as discussed above, but to a much smaller extent because the people that benefit is a very small number of people. The parks SEES and can quantify the economic benefit. They do not, however, in my opinion account for the problems it causes with negative feelings and image from the guests who cannot afford the perk.
The bottom line is always . . . well . . . the bottom line. Disney promotes guest experience, image and customer satisfaction as top priority and they see it as the best way to make money by promoting top notch service and high quality and value. They have a higher gate price, but reasonable food and other items. Cedar Fair seems to be focused on gate receipts and how much cash is piled up at the end of the day. Maybe they should focus less on making money today so that they would make more money tomorrow?