Lifting a car literally raises it higher from the ground. This can make it easier to see when you’re driving, improve comfort when driving on rough roads, and provide you easier access to your undercarriage—which is especially useful for a Smart car.
At a higher center of gravity, however, you’ll likely experience somewhat less stability when driving, especially when you’re cornering. You’re also at a higher risk of rolling your vehicle. Additionally, lifting your car usually means adding bigger (and heavier) tires—and while that look is especially cool on a tiny Smart car, it can also impact your pick-up speed.
Ultimately, there are pros and cons to lifting your Smart car. If you can manage a modified style of handling, the cool look and heightened performance of lifting your Smart car may well be worth it!