My opinion? Absolutely!
Maintaining a rigorous and diversified practice routine is essential to becoming a well-rounded musician. “Classical” exercises will translate much needed technical skills into your jazz playing.
A Strong History Of Classical Study
Many beginning jazz pianists may not realize it, most of the truly great jazz masters of the 20th century were well-studied musicians.
If you listen carefully, you can hear references to Beethoven of Schubert within Keith Jarrett, Bill Evans, Chick Corea, or Oscar Peterson’s playing.
Oscar Peterson could sit down and discuss at length almost any musical style, including slight variations in the sub-styles of different pianists of his era. Not only was he aware of this information, but he could sit down and play in any of those styles as well.
Technique, Technique, Technique!
Jazz players who don’t practice technical exercises don’t realize the importance of those exercises for developing sound technique over time.
While many argue that exercises like the Hanon piano studies aren’t “useful” for jazz soloing, and therefore aren’t worth practicing, they miss the fact that the point of the exercises are to develop agility and quick-response for each finger of both hands.
Just because you can’t quote the exercise in your solos doesn’t mean it isn’t worth it. Can you imagine a pianist breaking into a Hanon lick in the middle of Beethoven’s Emperor Concerto? Me neither.
Finally, no matter what your preferred style is, the simple act of diversifying your practice routine is an essential skill to develop.
Work the Hanon and other classical studies into your routine for a few minutes every day, and over time you’ll be able to see the results of the practice filter in to the rest of your playing.