Two years ago we "needed" just the right dog and we went to our shelter. There was a not quite full grown male APB pup who was just finishing a course of meds for a stomach issue. He looked so dejected and nobody would pay attention to him because the sign said "Pitbull". I wandered over and talked to him as he meekly came to the front of his "cell".
We couldn't take him that day but I promised him we'd be back the next day when we could take him home. I don't anthropomorphize but I swear he understood.
The next day when I walked in and said "hi" to the staff member, he jumped up and wagged his tail, but calmly waited. I had a collar in hand and when the door opened he came out and shoved his head right in the collar.
Our "need" was as a companion dog for my autistic step-daughter. I know it may scare the heck out of some folks, but I worked with him for several months training him. He goes outside with her, sleeps in her room, and is a good watchdog all the way around.
Experience with dogs cannot be undervalued when picking one out. I wouldn't say that any/every PB would be a good choice, but I won't say that no PB is suitable for this role.
Despite the fact that he is all muscle he is far easier to handle, and I trust him more, than some dogs, of supposedly "friendly" breeds, I have known.