Another way to think about this: consider why we don't use straight closing pins. If the pilot chute deploys as intended, a straight pin would not pull out because the pull would be perpendicular to the pin. With a curved pin that's not a problem, because it will rotate to stand up then slide out of the closing loop - unless the eyelet is on the grommet. If the eyelet is on the grommet, the tension on the bridle might not be sufficient to make the pin stand up so it can slide out of the loop. You would then have a pilot chute in tow. If the eyelet is just off the grommet, i.e., pin inserted 1/2 to 2/3 into the loop, the eyelet can turn when pulled because the fabric will deform on the side of the eyelet opposite to the bridle to allow the rotation, unlike the grommet which is not compressible or easily deformable.
