I defy you to make a real crossover with only one turnout.
Logically it may have only two states, and one JMRI "turnout" definition may suffice to control it. But, having the JMRI configuration not match the physical one only makes it that much harder for us newbies to fathom how all this works on our physical layouts... One to one mapping is much easier to understand!
On a sad note, I learned today that Sudro Brown has passed. He has been mentioned here as a JMRI expert in central Massachusetts. He was a local JMRI hero. Hearing Sudro demonstrate and expound the advantages of JMRI is what made me consider trying it. He'd say, "If you're not using JMRI, why aren't you?!"
I will miss having a JMRI expert in my NMRA division covering Connecticut and part of Massachusetts. It makes me even more appreciative of the time and effort knowledgeable members of this group spend helping the rest of us. Thank you all!