That's nice but they're not always available to roll with. I mean if you really want to train you have to go to the gym or have a training partner living with you or at least living close to your house. A year ago my friend had the same problem just like you. I can't roll with him because I'm just a MT practitioner back then. Then he decided to buy a grappling dummy, I think it's the submission master. Problem solved. You have a place to train, right? That's a huge advantage, having a partner and a place to train.