I think the answer to your question relates to the ability of the billionaire to do what he wants on his terms.
You have to ask yourself what are the implicating consequences of this kind of concentrated influence?
So I think in terms of consequentialism, you need to look bigger. Should the billionaire be further rewarded for philanthropic actions? What else would he have done with the money without those rewards? How do the rewards to big donors affect the donations and volunteering of smaller participators? What was the long lasting consequence of the big donation which awarded rewards to a big donor?
The answer to that is complicated, but could change the consequence of the system, so are relevent to a consequentialist perspective.
Of most noteworthy to me, I think is the idea that a single entity can have so much concentrated wealth in the first place, where we now need to put motivations in place for them to give it away. Why award so much wealth to that entity to begin with? What consequences does this has on the moral objective you're looking to get as a consequence of our system?
And so, if you believe having billionaires generates overall bad consequences, then you'll want to demotivate people to become one, thus you might start by shaming them for their wealth, by conveying to their ego that they are not special, loved or admired for those traits, and that their big donations is frowned upon, that we'd rather they just volunteered their time, because no one cares to know how much they were able to donate.
But, if you frame the problem in the small, and don't explore alternatives, or quesrion the consequences of the given frame, ya, a billionaire which gives hundreds of million to charity in exchange for a thousand of dollar statue is an all around good deal for the charity in terms of consequentialism.