From time to time, a CEO will have to choose between increasing employee compensation and benefits or increasing profits or dividends. The CEO works with employees all the time and most normal human beings would naturally tend to side with the employees because they're the ones that are working hard to generate the profits that the shareholders receive. Stock options create a financial incentive to override that tendency, so that the CEO will side with shareholders more often.
An interesting thought experiment is to consider: what would happen to a CEO if he or she refused to accept stock options and would only agree to a modest salary? What would the board of directors do? Would they be happy that the CEO is being a responsible steward of the company's finite resources, or would they regard the CEO as untrustworthy and remove him/her at the first opportunity?
Perhaps stock options aren't a "reward" for services rendered, but in fact one of the necessary qualifications for holding the office.