$25 may not seem like much money, but not everyone can donate that. Some people would really love to donate, but their parents are too strict, or they just can't afford it at the moment. Honestly, I don't care if others reap the benefits. All of the money is going to the same place: PC. That was the only reason I donated in the first place, but now I'm actually using the perks that come along with it. I don't mind allowing others to reap the benefits by donating for them. I don't really have a reason to reach tier 6, so it might as well go to people that want VIP access.
I've only donated for one person, but I wouldn't be surprised if I end up donating for more in the future.
Edit: Oh, and Nica, I unintentionally used Larry's word "reaped," okay? I didn't steal it. I was only looking at the post right above me when I typed this. :P