I didn't want to make mine permanent or in any damage the integrity of the bench. The piano and bench both had beautiful inlaid designs.
I made a fitted slipcover type of cover. The padding was separate and in it's own cover fit to the top and around the corners of the bench thus the top of the bench was really protected from harm. Then the 'real' decorative cover went over this. It made it easy to wash and I could change outer decorative covers with the seasons if I wanted to.