That’s a big positive if it gets instantly flat, with no creases.
I’ve made several toppers with 1/4” closed cell foam, with waterproof outdoor fabric attached on the playing side, and a faux leather backing which prevents sliding. Both adhered with 3M77 adhesive or an equivalent product.
This has been great, in that the tops are completely waterproof, and pretty much stain proof. It also allows for an overhang of cloth around the table, so the foam edges don’t fray. After adhering, I trim the fabric so it hangs 5-6" below the table top. (This also looks a little less poker-y in the house, if I don’t remove it right away after the game.)
However, my closed cell foam tops have not liked being rolled for long, even loosely. It is easy to develop either long-lasting or permanent creases. I’ve solved this by putting a few grommets on the overhanging cloth, and hanging the topper between sessions on a basement wall.
So it would be awesome to roll neoprene up without worries about creasing. My remaining concern would be those edges. Do you think you will finish your edges in some way? Or does your setup make that a non-issue by dropping the sheet into an insert?