I needed one to bind my Dx5e back to my park zone corsair, after i bound it to my ultra micro. then i found (after i had made one) that even pliers would have worked to put the rx into bind mode... its still easier to use the bind plug tho. so nothing much special about it besides me thinking (still beginner when it comes to hardware) that i absolutely needed one.
still glad i got creative and made one tho
The way this works is the transmitter has a GUI, Globaly Unique Identifier code. The receiver learns that code during the binding process. Once it's bound, it continues to look for that code and will only work with the proper transmitter. The receiver can be bound to any DSM2 transmitter, but the transmitter never ever changes.
So, once you have bound a model to your transmitter, you can also have another model bound to that same transmitter. You don't have to rebind. You just turn on the transmitter first, turn on the model you want to fly and once it sees the proper GUI code, it should come to life. There's no reason for constant rebinding. Even if you are swapping the receiver from plane to plane, it will remain bound to that transmitter.
I have a DX5e that I flew with a Super cub, and Ember 2 and an MSR and I never had to rebind to anything. In fact, I left the MSR plugged in and started flying the Ember 2 and the MSR took off. The thing I had to worry about were the dip switches. Now I have a DX8 with model match so those things are no longer problems.
I would caution against leaving a bind button in the model because it may actually cause problems for you down the road. If you find yourself constantly rebinding things I would try to figure out what's going on.