It does look like really good material. I do wonder how friendly it is to bare feet and its longevity to UV exposure.
Good point. It's so cheap it can't hurt to give it a try I suppose. I might use a butane torch to melt the edges a bit and make them less pokey.I've used duraslat for beaver tails and in drop bags. Works great and is cheap. Not sure how solid it would be in a cockpit, might have to run webbing under the middle of it to help support it. Dunno, for $20 you can experiment. Use a circular saw, cuts like butter. Murdochs usually has it.
For those contemplating marine vs cdx vs underlayment.
Cdx is the bottom of the barrel grade. Inner cores have a lot of edge and inner voids to trap water. C face, D back and X core. If it's 5 ply it may have 1 D center and 2 X cores. You'd be surprised at the crap cores that get layed up in CDX.
Underlayment has fewer voids. May have solid knots in the core. Allowable edge voids are much less than CDX. The voids are usually removed from the face by plugging. I don't recall the number but your limited to the number of plugs that can be on a face. Keeps high heeled shoes from poking a hole through a knot. Not a big worry on a raft.
Marine grade usually has more but thinner layers and a clear face and back. Very few if any edge voids.
Bottom line it is the number of voids and not the strength that makes marine better for wet applications. Although more thinner layers are stronger.
I wouldn't use CDX on anything exposed to elements. Underlayment is fine if you seal all the edges and exterior voids. Marine grade still needs sealed but it is prettier look if you care about that. Overall I'd choose a good 5-7 ply underlayment and seal any voids and the cheapest and most durable material for a raft.
That stuff looks like strand board. You'd want plywood graded for subfloors or underlayment. B grade faced plywood would work great but it's usually hard to find. AC grades should have C cores and the edge and back voids should be easy to seal.