Why do musicians often group instruments by playing method instead of by sound-production system?

Musicians often group instruments by playing method rather than by sound-production system because it is more logical and practical for their professional needs. While systems like the Hornbostel-Sachs system are essential for scientific classification and organizing ethnographic museum collections, they are essentially arbitrary, much like library cataloging systems.1

For a performer, the physical interface of an instrument—how it is held, manipulated, and played—is the primary concern. Consequently, musicians naturally categorize instruments based on their technological features and playing techniques. For example, they group all keyboard instruments together because they share a common method of interaction, even though those instruments might belong to entirely different categories under a sound-production classification system.1

This preference reflects a focus on the practical application of music-making, where the physical demands and technical fluency required to play an instrument are more relevant to the performer than the underlying acoustic mechanism that generates the sound.12