I train martial arts several times a week. Usually it's a combination of wrestling, BJJ, and MMA with some boxing thrown in. My motivation was initially fitness. I hate going to the gym, so I thought grappling and wrestling would be a great alternative - which it is. I'm building functional strength and muscle while also acquiring 'self-defense' skills at the same time.
Martial arts also let's you know your limits. For instance, I've been boxing way longer than I've been grappling, yet when I picked up martial arts again, I discovered it's actually my weakest discipline. I learned that it's not even about how hard you punch, but timing. When sparring I kept getting caught my smaller dudes. They weren't hurting me, but I kept getting caught.
I also learned that grappling is my strongest suit which I had no idea before I started. But in my first week of training, I remember two different dudes on separate occasions jokingly telling the coaches not to teach me any BJJ

. I'm a 6'2 220lbs guy but lean and muscular. But somehow they already knew I'd be a threat. I was controlling white belts and blue belts easily. I couldn't finish purple belts, but I could defend myself without getting submitted.
So I know my limits and know that boxing is what I need to work on the most. I don't walk around with a false bravado thinking I can beat on anyone. In fact, I'd be the first person to try to deescalate a situation. Fighting is not worth it in any situation. Having a weapon is always best, unless you're caught without one and are left with no other option than to fight in a given scenario.