I can spend a divided. Especially if I have to take a mandatory distribution. You have to sell (at the right time) to get profit from a buyback

You are forced to pay tax when you get a dividend. Buybacks allow you to sell over time and achieve the same thing but with preferential tax treatment in most jurisdictions.

Or more importantly not sell at all and not be forced to pay tax when you are just going to re-invest the dividend.