They are completely different with respect to their impact on stock options.

If you hold stock options, a dividend doesn't benefit you. You need to hold shares to get the dividend. In fact, the dividend can cause the share price to fall (if it was not already anticipated) as the company's capital gets drained to pay shareholders.

On the other hand, buybacks (causing a sudden, surprising increase in share price) are most impactful on those who hold options. Proportionally speaking, they increase the value of options much more than the value of shares. The share price might go up 2%, and the options 200%.

Executive compensation packages tend to consist of stock options. So buybacks benefit corporate insiders more than shareholders.