This year is the first time I've taken cardio seriously in my routine and I feel by no coincidence, I'm in the best physical shape of my life. With cardio, I've been able to put on much more quality mass. I've never had trouble putting mass on, but it looks much better this time around. I'm 5'10" and it's going to have a role in allowing me to finally hit and surpass 200lbs while being around 10% bf. Indirectly, I feel it's helped my weight lifting routine as well. I can't put my finger on why, but maybe with the higher endurance you receive from cardio, you get a higher quality work out with your weight lifting routine. That mite be broscience, feel free to discuss if you feel different. As I said, running 3 miles, 5 times a week has been the sweet spot for me, so nothing too outrageous.
That's been an unattended consequence. You feel good physically and psychologically from running.