The setting that burns bread to a blackened crisp is often referred to as the "maximum" or "dark" setting on a toaster. While it may seem counterintuitive to have a setting that burns the bread, it serves a purpose for those who prefer their toast well-done or crispy.
The reason for this setting is to cater to different preferences of consumers. People have varying tastes when it comes to how they like their toast. Some prefer it lightly toasted with just a hint of color, while others like it thoroughly toasted and crispy. By including a maximum setting, toaster manufacturers can ensure that individuals who enjoy darker or crispier toast have the option to achieve their desired level of toasting.
It's essential to remember that the settings on toasters are adjustable, and you have the flexibility to choose the level of toasting that suits your taste. If you prefer a lighter toast, you can set the toaster to a lower setting to achieve the desired result without burning the bread.