When learning 180s and other spins you should have a pretty good comfort level with switch riding (which it appears you have based on the fact that you can ride greens switch). I would continue working on that skill as it makes you a much more diverse and confident rider.
I voted "no" because it is necessary for everything, but in order to advance to the next level you will need to be pretty comfortable riding switch. A good way to do this is to try riding switch whenever you are riding with people below your skill level (aka . . . going with your girlfriend? Ride switch).