My first reaction to your remark was to respond that you're wrong, that for the most part work on open source is separate from work for pay, and that people do it in their own time out of intrinsic interest and not out extrinsic reward overcoming intrinsic indifference.
Paying them would then be pernicious and wrong because it changes there story from "I do this because I'm good at it and value it" to "I do this for spare cash", and I've seen that have a bad affect on people. Their intrinsic sense of reward and their own story about themselves is changed into a sense of extrinsic reward.
What stops me from saying that whole-heartedly is that there *are* aspects of writing software that are essentially unrewarding for many people, and intrinsic interest in making something work (especially just for the person writing code) is very different from the activity of making it work for everyone. Some people will do it from altruism, but many people will get it working good enough for their own needs and be done with it.
So in that turning-the-crank, grinding-out part of the task, maybe there's room for something like this service... though there are other services like it, as others have already pointed out, and I agree that the name sucks.
If I had a mod point, I'd mod you up.