Uh, good publicity? A cheap way to wash off his name? (the attitudes I see about him in Seattle are surprising, even to me, even after being here a while). A great way to buy good publicity before steadily reducing your workforce through automation over the next decades as is surely the plan?

Bezos has shown few, if any, signs of altruism and the one instance I can think of would be roughly the monetary equivalent of me giving a homeless person a penny.