At our local game store, we asked the owner who purchases deck protectors. Expecting to hear that it is mixed from and card players to board game players, we were caught off guard when he responded that it was mostly the people that play card games, i.e. Magic and the likes. Well, that just floored us, so Marty and I decided to use this 5 Minute Initiative by giving a PSA for deck protectors and how and why they should be used in protecting your board games that use cards.
Now we will admit that sometimes they are not practical for every game (ie Dominon) due to what it does to storage and so forth, but for games where your cards are constantly being pawed at, Cheeto molested, shuffled, tossed, and even snorted to remind us all of what rainbows smell like, why would you not use them.