Their rate of fire is usually poor relative to that of machine guns and submachine guns, but they can still get the job done if your aim is good. Unlike most weapons, pistols are very cheap. They tend to deal high damage from close range and against unarmored enemies, but are weak from afar or against players who bought kevlar and a helmet.
The pistol is your secondary weapon and whether you’re a Terrorist or a Counter-Terrorist, you will need to know how to use it because it gets used a lot. The best pistols are probably Desert Eagle and USP-S, although each player has his favorite options.