Example,
Someone falls in the hallway you have no insurance.
Someone fake falls and sues in a fraud case you still have no insurance, because of uneven floors etc.
Laundry room bills too high due to cold dryers from condensation, tennants can sue over that for cash refund or rent reduction.
Updated, now they got the back stairs full of garbage and not cutting the back lawn.
If a tennant has to weed wacker the back yard himself to have a barbecue building maintainence is fired.