I was homeless for 9 month in Paris (until i got my first internship), i did not live on the street, i slept at my school or took friends beds when they were out of town, and i think most homeless do the same. And i was not alone, i think we were ~20 to do the out of 400 students. None of us had addiction (i can't tell about mental issue, after all we wanted to be devs).

I went to San Francisco 3 years ago with my familly and my sister made some homeless friends. They were not living in the street but in their cars, they had low-pay (or illegal) jobs and did not seems to have any addictions.

I think this is a definition issue. Homeless just mean you don't have a home.