Polygon and NURBS both are necessary for each other.NURBS is also like a smooth shape and can be manipulate according to required object.
Here you can find separate keys and attributes to shape the object, e.g. Maya fluid effect help you to simulate fire smoke cloud. Similarly Maya Hair and nCloth help you to create hair as human have with the help of curve and paint effect and nCloth used to give cloth material.
One of the greatest aspects of the 3D animating software Autodesk Maya is that it has ability to do what other software of its class can not do. You can do any type of modeling in the Autodesk Maya, blend any object with other. Moreover, Maya offers you Maya Mel (Maya Embedded Language). And you can work in Maya in the coding form. This language is much easy than C++ and the Python. Autodesk Maya can be learnt by the books and other institution but it is very easy and comfortable for you to learn Maya by the video tutorials. There is another advantage to learn Maya here that you are kept updated with the latest improvement. www.freemayavideotutorial.com is the website which is doing an excellent work and teaching Maya with providing free tutorial videos and in online classes.