It’s a neat concept, but I think the microwaveable ones have a shorter longevity. They say it can only be microwaved around 5 times. I suspect they just work because when heated, the erasable ink becomes invisible.

On the normal pocketbooks, the ink actually washes off with just a bit of water. It’s very similar to a whiteboard in that regard. I know I’ve cleaned out my notebook more than five times, it’s still basically good as new. Except one page where I accidentally used a normal non-erasable pen.