They have the ability to provide a more comfy ride.
Tires with a greater sidewall, such as 18-inch tires, are often more elastic than those with a narrower sidewall. when driving over hills and bumps, your tires work as shock absorbers and, therefore, can give more cushioning. Moreover, they may be less harmful to your engine.
Because
18-inch wheels are lighter, your engine might not even have to work as hard to accelerate your vehicle. They might also aid in the reduction of wear on the suspension and braking systems.