肖邦和李斯特的練習曲一般都被稱作「音樂會練習曲」，這些作品既有較高的技巧，又有很高的欣賞性？

True, but in modern day, their effectiveness has greatly paled, simply because they are too over-played, and almost every performance sounds the same. While they are undeniable musical values, they have little rooms for creative explorations - meaning, there isn't much you could manipulate in the music, and hence most performances sound the same. Chopin's Etudes were not meant to be performed in public, and Liszt never put his own Etudes in his own recital programmes. However, they are usually better appreciated by pianists rather than a casual listener because they usually sound easier than it actually is.