Dear Mr. Crook and List,
I am an enthusiastic advocate of trumpet Etudes for the following reasons.
1. The finest Etudes represent music written by, and for, trumpet players, and as such, I consider many of them to be among the "best music" extant for the trumpet. The are supremely "trumpety" (to coin a phrase).
2. One important purpose for "the etude" is , in my estimation, to push us far beyond that technical level which is required for most of the trumpet repertoire!! For you see, when we have mastered the difficulties of Walter Smith's 30 Top Tones for the Trumpeter, for example, there are precious few pieces from the major repertoire that will appear particularly daunting to us, by way of comparison. Endurance, perhaps, is especially a factor. Again, often we are pushed to the limit!
3. The etude allows the composer to highlight and develop certain problematic areas of performance - while a tendency to "avoid" these problematic areas is characteristic of most composers. In other words, by highlighting "difficulties" and forcing the player to develop the skills to meet the requisite demands, the composer purposely confronts us with "difficulties" that would be carefully avoided in a "purely musical" context.
4. I would be careful to differentiate between and "Etude" and an "Exercise" - the difference being the extent to which the composer balances his materials. Most of ARBAN, the Characteristic Studies excepted, consists of exercises. Most of Sabarich's DIX ETUDES, Charlier, and Walter Smith (among my favorites) are Etudes, or even compositions for unaccompanied trumpet . It seems to me that BRANDT 34 Studies tend to be more of a combination of "etude and exercise" (Please don't read this as being a "put down" - grin).
Keep 'Em Flyin'!