There are two, and only two types of spaces
1) Private spaces.
2) Public spaces.

When you can not afford to pay for a private space, the only thing left is public space.
The human body requires sleep to exist. Sleeping requires some level of comfort to reach REM and be productive sleep. blankets, pillow, etc.  Otherwise the body does not get the proper rest. 
There are many others that have experience with deliberate and extended periods of time where they were forced not to sleep properly. They suffer from PTSD from being tortured during the wars. We have now legalized public torture of the homeless by preventing them a place to sleep without being rousted and forcibly moved over and over.