I suspect this could be a reference to the way Murex sea snails have been historically used to obtain Tyrian Purple dye. The dye is obtained from their mucus, IRL, so if a similar mechanic were added to the gameit would likely make sense if using the snail in a caldron or maybe a furnace would give the player a 'royal' shade of blue, purple, or majenta dye. But that would consume the snail and not also produce snail flesh. I'm guessing the original suggestion was to use the snails as a substitute for the deep blue Lapis Lazuli dye.
But, this could have been explained better in the original suggestion.