Note that this uses friction resistance. Essentially, two pads surround the wheel, creating resistance. The harder the pads press against the wheel, the harder it is to pedal. The only good thing about using this cheap older technology is that it doesn't need electricity.
I much prefer magnetic resistance, which uses electricity to power magnets. First, it's VERY quiet and smooth. Someone sleeping next to me would not be able to hear a bike using magnetic resistance. Second, it's arguably less prone to breakage. Depending on your usage, pads often wear out. The wheel is rubbing against it constanly, after all. In fact, a 5-resistance when the bike is new may be harder to pedal than 9-resistance when the bike is older. The dial, then, doesn't offer a good measure your progress. Third, you can control the resistance with a computer, which makes for a more effective and interesting workout. My bike, for example, can simulate various terrains, i.e. uphill, downhill, flat. Or it can slowly ramp up the resistance. Or it can automatically increase resistance until reach your target heart rate, whereby it'll ease things. This helps you keep within the perfect zone for weight loss or aerobic exercise. A manual dial that controls friction can't do that.
Lastly, bikes that use cheaper older friction resistance often have cheaper displays and monitoring systems. While some don't care about bells and whistles, a fancy computerized display motivates me.