I don’t know anything about shellacing cork. But shellacing cloth tape definitely extends its life. Keeps it clean and unstained, keeps it from unraveling and peeling up on the edges. Some people (me) like the deeper dark look of it. Some people (me) like the feel of it.
But I’m not being completely honest — on a couple of occasion I had problems with the bars getting completely soaking wet. The shellac eventually absorbed some of the water and became white and cloudy. Very unattractive. I acquired doubt.
So a couple years ago when I last re-taped the bars on the Riv, I used polyurethane varnish. Not ecologically correct at all. But very tough. Nice feel, nice look. It may never come off, but it may not need to.