A lot of people here are questioning the data of the study, but don't actually seem to be looking at that data?
Yes, the control group, who received less money, also did well in some metrics, but in most metrics they also started off better, so the delta in their experience is in fact smaller.
Furthermore, the control group also experienced a drop in full-time employment, while both of the subject groups experienced gains.
I agree the headline isn't a useful representation of the importance of the data, but it does seem like this was a fairly impactful program.