An instrument like this could actually change the way all pianos are tuned. Contrary to what you may have learned in Disney's Donald in Mathmagic Land, choosing exact frequencies for the notes in a scale is far messier than tuning the strings to the neat fractions of the Pythagorean scale. Tuning an instrument very exactly to one key using the standard ratios between notes makes it out of tune in every other key. (There's a very good, non-animated summary here.) The modern scale simply splits the difference between every key so that they're all equally out of tune.

The AvantGrand can instantly retune itself to a variety of tunings, or "temperaments," from Donald Duck's Pythagorean scale to those that were standard during Bach's lifetime, which is very titillating for baroque-enthusiasts. Those wishing to precisely re-create the tuning that Bach used can hit a few buttons on the control panel, and the pitches of the notes will revert to the asymmetric tuning used in the very early days of the piano, when different keys had different personalities, since they weren't all equally corrected. Are you a devotee of the 17th-century organist Andreas Werckmeister? You can set the piano to his preferred frequencies if you like. The AvantGrand even has a harpsichord setting that, like a real harpsichord, produces the same volume no matter how hard you strike the keys.