[ChefboyOG]

The "undo" functionality, in my experience, is not amazing because it provides an enhanced eraser. It's amazing because it allows you step backwards through your free-hand thoughts.

As an example, I routinely use my tablet like a whiteboard for working out bits of math. The ability to bring back a value I'd previously erased to see exactly where I miscalculated is extremely useful. Similarly, I find this sort of thing to be really helpful when whiteboarding my way through a particularly thorny programming problem at work.