Try doing that with a Eb instrument like an Alto sax and tell me how you like the fingering :) Also, as the article says, this allows players of an instrument

Try doing that with a Eb instrument like an Alto sax and tell me how you like the fingering :) Also, as the article says, this allows players of an instrument that has different versions with different tunings (e.g. saxophones which can be in Eb or Bb depending on the type of saxophone) to learn one set of fingerings and being able to reproduce it on all tunings. So, for example, a written C is done by pressing all but the last button (iirc). By doing this you'll play a Bb on a tenor sax and an Eb on an alto, but with the score being transposed you'll know that when you see a note one line below the staff you'll have to put your fingers in that position regardless of the sax you're playing.