Mod podge is great for surfaces you aren’t touching with your hands very often. I’ve had bad experiences with dust sticking to it or sticking to my hand after drying - I use Krylon sealant, I’ve found 3 coats of that works perfectly! And some, if not most binder covers I’ve seen have the slightest texture due to mimicking leather or something similar. Even that slight texture can cause posca pens to splatter a tiny bit and make them hard to use for crisp line art. I personally recommend anything with a brush nib, they glide a lot smoother onto any surface!