Why not use the engine of a model aircraft for other purpose? I was reading the DLE-120 engine User Manual and saw this sentence:

This engine was designed for use in a model aircraft. Do not attempt to use it for any other purpose.

Why? Why not use the engine of a model aircraft for other purpose? What does mean &quot;model aircraft&quot;? Does this mean only RC aircraft or RC and UAVs?
Is there any technical or safety reasons why this engine could not be used in a different application, not involving a model aircraft?
A lawyer wrote that. It means if you use it for any other purpose, they are not liable and you are.