If you want to know whether the model is useful, just make a test setup in simulation and see what happens. You may start with the DC characteristic (forward voltage at some diode current). When this looks OK, just simulate the insertion loss in a typical setup (for example 50 Ohms source and 50 Ohms load at varying DC current). You may also simulate the insertion loss when reversed biased to assess the capacitance of the PIN diode.
I don't know ADS, but in my PSPICE there is no good PIN diode model. Just to verify switching action in a circuit, I play with the transit time (diffusion capacitance) and junction capacitance parameters and set bulk resistance by hand to get the datasheet's Rs at certain forward current. If course you need to know how the model functions, otherwise your actions will not converge.