The press n seal is only important if you lose a lot of moisture through evaporation. I've hatched plenty of ball pythons without it, but I've also lost clutches in the past when the egg box dried out with a couple of weeks yet to go before hatching. Once the eggs desicate, especially late in incubation, it's tough to get them plumped up again. The lids to most shoe boxes don't have a very tight seal, hence the press n seal.

I've been doing a bit of research on this superhatch substrate and I think I'm going to have to get some to give it a try, it sounds like it should be pretty effective. I think I'm going to set up a couple of boxes with it this year to see how it works out. Thanks for the tip.