It's a limited return to an economically more primitive era - the barter system. Nobody necessarily "profits" on either side; you simply exchange what you've got for what they've got, and both sides walk away smiling because they were low on what the other one had.
Of course, it would be a rather grave tactical error to assume that the world would be much better if we'd all just give up this whole "money" idea and everybody do stuff for everybody and we'll all be happy. Agrarian feudalism had its own set of problems, not the least of which is that it couldn't FEED all the people we've got on the planet today. And really, in all honesty this sort of thing is by far the most effective for relatively high-margin and service-oriented enterprise - goods-oriented enterprises, which are typically much lower margin, require far more careful accounting and can rarely indulge in the quaint comfort of a simple barter.
But still... it's a curiously nice feeling to go to your doctor or your CPA and not have to worry about "can I afford this", or "am I getting ripped off", or etc, etc, etc - it's so much simpler and more pleasant to simply take care of one another. And it makes you feel valued in a way that receiving money rarely if ever does.