1. The people that tend to stay in boarding houses tend to be on the lower end of the socioeconomic scale.
2. This kind of arrangement can be very good if the market is right. Would it work in Beverly Hills? No. Would it work in the Dakotas near the oilfield/pipeline work? Yes.
3. PITA. You would have cleaning, repairs, restocking and policing to do every day. Probably takes 30 minutes to 4 hours a day to run it. You'll be dealing with vomit, dirty toilets and sinks, clogged drains, drywall repair, double or triple occupancy in a single occupancy room, dealing with the people that are the causes of the aforementioned things, and probably complaints from neighbors.
@Paul Sandhu Thank you so much for you feedback, That's a lot to think about. I'll do more research on rooming houses in my area and see if it's even worth it. Thanks again.