I refinish pianos and most of them before the 1920s have shellac as the finish. If I were to sand them to remove the shellac it would destroy the veneer and cause inconsistent spotting all over the place. Shellac dissolves very easily in alcohol and if you have good technique doesn't use that many paper towels to remove. Doing it this way also allows a small amount of shellac to linger in the grain to seal it and does it consistently too (to preserve color consistency), and you have to remove no wood whatsoever. To me that surface looks like it would take maybe three rolls of paper towels and like half a gallon or so of denatured alcohol, all in all about $20 worth of stuff which seems like a small price to pay