Benefits to no M

From my own experience and some of my friends that I've spoken with, M can act like a gateway drug if porn addiction is in your history. It may be only a matter of time before just M doesn't do it for you anymore and you'll be hungry for more. I think this is one of the best cases to abstain from M. It's difficult (or darn near impossible) to M without any sexual thoughts at all. Those sexual thoughts are often visual, which is essentially imagining porn. As I said earlier, there may come a time where that just isn't enough. Besides, those sexual thoughts may be feeding into the pathways in your reward center that you're trying to starve.
Porn and masturbation are closely tied. You may have the strength to just M for a long time, but I think you'd be teasing yourself. Sexual temptation is incredibly strong, and I think it is best to live in doubt of your own strength and take precautions rather than step up to the line and try to stand your ground.
It's up to you. From personal experience, just M did not work out for me. Maybe it can for you, but do be careful that you're not convincing yourself to do something that will lead to disappointment just for some momentary pleasure.
Take care.