Aside from the fact that having a safe place to live alone helps both mental illness and substance abuse in most individuals, a major cause of homelessness is domestic abuse and being disowned. Having a safe place to live will absolutely help the over a third of domestic abuse victims who become homeless, and would help those who cannot afford to get away from their abusers due to lack of ability to find a safe haven.

Home the homeless, then we can start working on the harder parts.