Tires are the middle man between the car and the ground. They are key in good control and maneuverability of your car. So is bigger better? Perhaps the disadvantages outweigh the advantages of larger tires.
Increased tire diameter means increased moment of inertia. This means that there is more of a resistance to speed increase and decrease. Your acceleration may feel smoother, but your brakes will have to work harder to stop your car, which is a safety concern.
With larger tires you have increased clearance. Clearance to some people is a huge plus. Some people are avid off-road drivers and need larger tires to navigate rough terrain.
The main reason for larger tires/wheels is purely aesthetic. Larger wheels are visually appealing, especially with chrome rims and low-profile tires. Particularly with trucks and SUVs, large tires can enhance the look of the vehicle.
Your brake system, stability system and speedometer are all calibrated for a certain tire size. Changing your tire size can cause all of these to work improperly.
