>>1990463thicker gives better bang-for-the-buck shock absorbtion. suspension is heavy and really only works well for gnarly big hits offroad. for anything you'd find on road, tires (and lifting your butt out of the saddle and letting your knees and elbows help absorb) is better .
the science is in: the pro roadies used to run 19-23mm tires and the higher pressure they require. now the standard is 25. absorbing lots of tiny hits instead of bouncing off them makes you faster over the course of a race.
I ride 32mm and its comfy, I can do gravel and off-road competently, too. if you're goal is going fast or racing I'd stay with 25s though. for dedicated off-road bikes, you'll want greater than 32 for sure