Mr. Beast doesn't do _philanthropy_, he makes entertainment videos. His niche is giving money away in exchange for challenges or stunts. This gets him views, and has created a profitable business for him. That's not altruistic at all, it's just a business guy who is quite good at knowing his audience and executing his trade. "thousands of people regaining their sight" is a glorified marketing campaign.
Yes, money goes to causes; but the fact that money wouldn't otherwise go there is a policy decision that we've collectively made. We could tax billionaires and use the revenue to fund health, education, housing, infrastructure, research, or whatever. I'd much prefer to see us do that than wait around until we see Mr. Beast's Children's Hospital pop up somewhere.