Actually, sometimes I like to use my trainer when I am working on learning or practicing a particular manuever. The reason why is because the plane is adding NOTHING to the manuever so everything that is happening is because of my fingers on the sticks. The trainer will force you to perform a manuever by the book and do it properly. Many more aerobatic planes will allow the pilot to get sloppy and still look decent. But trust me, when you can do a manuever on a trainer and it is done properly you KNOW how to do it!!!! Try doing a single slow axial roll that is the length of your runway in a trainer and you'll see what I mean!!

Ken