Happy to answer.
Silnylon is a ripstop nylon fabric impregnated with silicone. Which makes it VERY slippery. You can fold it if you have a lot of patience, time and a big flat floor to work with. And even then you are going to use books and your knees to hold the folds in place.
Stuffing is actually better option for fabrics. On thin durable materials it would take a lot of time to form creases and wear marks, but grab something like a cheap £6 tarp from ebay and you will have "corner holes" after only few uses. Same with sleeping bags, because the insulation is thick, if you fold it the radius of the fold can actually tear it inside and you can endup with partitioned sleeping bag with cold spots.
It's more convenient and safer to stuff the silnylon tarp in the bag. Especially when it's wet. It would take a little mor espace but a soft ball actually fits better in your rucksack.
I used to have siltarp 1 (1.4m x 2.4m) in my edc bag as a emergency backup, and it was easy to fold once so it stayed folded for months. But this 3m x 3.6m take good 20 minutes and a lot of sweat to fold neatly.
Longevity wise it's in the same box as the rest of the man made fabrics. It will last years of normal use. The only enemy silnylon have is UV light but again, nothing to worry about in real world. Maybe if you leave it in your garden for a full sunny year it migh start breaking down...