I think those are worth a lot because there isn't a comparable thing in the market anymore. At least there wasn't when I looked a few years ago.
I've never used one myself, just going off what the internet says about them. There are lots of reviews of them on YouTube (people either call them "l-tek" or "polish pads")
I ended up with the L-Tek one you linked. The buttons seemed awfully futzy to me, and she says they're ok but not great - plus her toes hit against the edges of the raised non-button squares and hurt.