I don't think it's surprising, but good research to have backing this up nonetheless. Pretty much every problem in this country can be traced back to the lack of affordable and stable housing. It makes complete sense to me that a state house with security of tenure comes out better than a private rental you know you have for a year at most (and likely less if no cause evictions come back).
Incidentally, the authors of this study have done a lot of research into housing quality too. They found that providing insulation grants for our notoriously cold and damp houses generated savings many times the cost due to less pressure on the health system and fewer sick days from school and work.