Thinner is faster, more of a chance of washing out.
Nice if you ride HOME from the trail. (street,dirt,street) because they are faster..............BUT, they blow on nasty terrain.
I notice more the Maxxis MONSTER tires on bikes. Roll OVER the rocks.
I like a thinner 1.95 rear-2.10 front. makes my ride nice, I do not follow the bike norm though.
Way easy to accelerate\ pull the smaller rear. And the big front mashes over objects\ curbs well. (in my case also a rear tire w\ more steering oriented treads)
My opinion? If more than 50% of your riding is street and speed is your main concern-yes.
Most other things considered mtb, no.