Waterproof Mattress Encasement vs Vintage Linen Bed Cover: which is safer?

Where these two actually differ

• We flag Waterproof coating leachates (fluorochemical or silicone-based), Polyurethane off-gassing (volatile organic compounds), Microplastic shedding from coating or weave and Mold or bacterial growth if encasement traps moisture on the Helix and not on the Parachute.
• We flag Azo dyes or heavy metal pigments, VOC off-gassing or odor and Mildew or mold growth if damp on the Parachute and not on the Helix.
• The Helix is Polyurethane/polyester fabric with waterproof coating (unspecified type) where the Parachute is 100% linen, no reported coating, which is most of the difference in these two grades.
• The gap is 45 points, wide enough that this is not a close call, and the Parachute is the one to buy.
• We are less certain about the Helix grade, at 45% confidence against 82%, because it discloses less.