You need at least four states to exploit the advantages of a Mealy machine over a Moore machine
With a Moore state machine, the number of possible output combinations (I hesitate to say "output states") is no more than the number of internal states.

With a Mealy machine, the number of possible output combinations can be as high as the number of internal states multiplied by the number of input combinations.

Whether one is an "advantage" over the other really depends very much on context. For example, in high-speed logic design (such as an SDRAM controller), a Moore machine is preferred because the timing of the outputs is much more tightly controlled.