Latex beds, breathable foundations, and dust mite covers

Hi, I just got a latex mattress, and am trying to suss out what to do with it, lol. I always use a dust mite cover, and it’s water resistant, because I have pets. In shopping for a new dust mite cover for my new, larger, mattress, I’ve found that there are dust mite covers with a polyurethane lining, which makes them waterproof.

So, if I encased my latex mattress in that, would I still have to be concerned about moisture and breathability?

Is there some reason not to do that? Why don’t people just do that, instead of worrying about breathable foundations?