The stabilizer allows you to relax a little more when on the highway. It increases the "reliability" of steering effects by dampening the wheels' response to paving irregularities. If you hit a pothole for instance, you'll often feel the steering wheel push left or right depending on how the hole affects the wheel that contacts it. That is transferred backward from the road to the steering wheel and you through the drag link or tie rod, depending on what the stabilizer is tied to. You can certainly operate without one. My old 1960 Ford F100 didn't have one and it steered just fine. There was no power steering though, and you could find yourself wrestling the wheel on a rough road or ground to keep a line.
