I ride places all over the country (when funds allow) and that can mean a huge variety in terrain. Different tyres undoubtedly work better on different conditions. These days I’m more happy to take a compromise (within reason) and find a tyre that’s more of a jack of all trades than running specific tyres for different terrain, but I can see why some people do it. The tyres are the bikes only contact patch with the ground, and other than the engine, have more impact on performance than anything else offroad.
I do use a set of dedicated mud tyres on my hardtail through the winter though, and they stay on until the trails are dry enough to warrant going back to something wider and faster.