Precisely. Playing the Etudes in retrograde also presents an interesting technical challenge.
Not again...Dan
The Chopin etudes in every key were something that Lennie had me start on in my early teens. After awhile, transposition of any music, standards, jazz solos, classical pieces, to any key instantaneoulsy became second nature.
This is a technique that works with every technical work the performer enjoys. It is not just the finger dexterity that gets cultivated, it cultivates musicality. The more you know on how to "do" this with what you are given, the more you get into actually reaching mastery of what you "play".
Bach WTC has often been used for that particular method of learning music. I believe that with some exceptionaly talented musician the process of transposing music happens in real time, however with less talented people this will take a little longer,and turns into music gymnastics.