The ability to create complex 3D models with ease, which are then used for testing purposes such as FEA or stress analysis etc..
Also very good tool when it comes down to creating simple geometries like cylinders/spheres/prisms etc., also have some nice templates available so you don't need to start from scratch every time! I think there's more features than what we use but they do offer different types of licenses depending upon your needs (ease of access). We mainly work within our own team using this software however sometimes other colleagues will ask us about their projects too - just give them an overview over how easy its been to model certain parts without having any prior experience at all!!