In doing so, you're betting that _you_ can grow your money faster than organizations you give it to can make impact on their communities.

Helping people who need it _now_ rather than in ten years helps _them_ start contributing more effectively to their communities, or blunts negative effects of them _not_ having that help for the next ten years.

Sure, it's a bet you can make that you'll grow your money faster than it would have impact being put into the world --- but it's one that takes a certain amount of hubris.