Polypropylene Envelopes vs. Paper Envelopes: Pros, Cons, and Best Uses Compare polypropylene envelopes vs. paper envelopes. Discover the pros and cons of waterproof poly envelopes and eco-friendly paper options for e-commerce and documents. Choosing the right packaging is more than just a logistical detail; it’s a decision that affects your brand’s reputation, your shipping costs, and the safety of your contents. When weighing polypropylene envelopes vs. paper envelopes, the .