If you’ve ever heard a musician refer to practicing “in rhythms” this is what they mean. It’s a very effective way to practice fast passages with lots of notes!
It should improve your playing in a number of ways:
1. Evenness—practicing in rhythms exposes the small transitions that can get in the way of a great performances. It also gives you a great way to isolate and practice a small chunk of music.
2. Speed—dividing the music up into small pieces allows you to increase the speed in a manageable way.
3. Facility—as you practice in rhythms, your brain becomes used to the specific patterns and they feel easier
4. Physical endurance—your body will become strong in the ways you need it to for the passagework
5. Understanding—as you play in small chunks, you’ll better be able to perceive patterns and exactly what is going on as you play.
I hope this helps!