What are the pros and cons if an adult child returns to live with his or her parents?

Apparently, in the US, particularly in the State of Virginia, there has been a 45% increase in the number of kids returning to live with their parents a few years after graduating from college. In Washington DC, it seems it is 18%.

The most prevalent reason is of course, the children have found it difficult to support themselves, not getting a job or if they did find one, was not enough to sustain their independent state.

So even if this sounds bad at first, could there be any good in these kinds of situation?