Some like it hot.
Like lava that seeps up from the ground, rather than a violent eruption, a good hot sauce will slowly build its heat around its flavor profile. Not everyone wants to burn their face off while scrambling for the milk jug. Different hot peppers will give you a different heat profile, combining the best peppers with ingredients such as carrots or peaches will temper the heat against the natural sugars of the fruits and vegetables you use. This is also true of the acids used in creating a good hot sauce.