Exposure of Fresh Soil
One of the benefits of mudslides is that they open up new and fertile ground for plants. This comes at the cost of destruction of other plant life, but nature is cyclical and destruction goes hand in hand with growth. The exposure of fresh soil can also be of benefit to those who, for example, use mud to form bricks to build dwellings or other structures with.
Less Likely to Happen Again
Another positive aspect of mudslides is that they are often cyclical in nature. The mudslide will happen, and then the conditions that made a mudslide likely, such as the slope of a hillside, are reset. Another mudslide, in the same spot at least, will then remain unlikely for some time. In this way mudslides, like earthquakes, are predictable to a certain degree. Having a mudslide means that there is less risk of it happening again in the near future.
New Geological Features
Sometime new geological features can be formed because of mudslides. Beaches, for example, can be formed by mudslides along the edge of lakes or oceans, and in the case of particularly big mudslides new land could even be formed in this way, similar to how the islands of Hawaii have been formed as a result of lava flow. Coastlines are popular places for human settlement though, so there is always the chance that destruction could be a part of this act of creation.
Examples to Learn From
Perhaps the biggest benefit that mudslides provide is that with each one studied researchers learn more about mudslides and more about how to predict and even prevent them. The creation of human settlements often changes the landscape and can create the potential for mudslides where none existed before, which puts those human settlements in danger. Mudslides can be mitigated or prevented entirely by learning from how previous mudslides happened.