When this port is made to run on another operating system, it implements a virtual Linux machine within that OS. As such, it represents an environment in which that OS can run Linux binaries.
A number of operating systems already have some amount of binary compatibility with Linux, and several have Linux compatibility environments. This is potentially another way of achieving the same goal. With Linux becoming the Unix development platform of choice, other Unixes are going to be looking for ways to run Linux executables, and this may be a good way of accomplishing that.