Plot hole: To rig blackjack card shuffling machines to make the dealer bust and everyone else get 20 or 21, its success would depend entirely on knowing the exact number of people at the table at that time. Perhaps the filmmaker is assuming all seats at the high-stakes blackjack tables would always be filled during a "soft" opening, but that seems extremely unlikely.
Plot hole: The rigged dice, while undetectable, wouldn't necessarily work. While they have the ability to turn the dice they still don't know what number the dice will land on and which way the dice will roll when triggering the lighters. Granted they can keep someone from losing by triggering the dice, they can't always make someone wins. And most of the bets that were placed (Rusty's Snake Eyes bet) are 1-roll bets, i.e. if you don't hit on that roll, you lose.
Answer: Linus was trying very hard in all three movies to prove himself to Danny, Rusty, and his parents. The nose is obviously his innovation, and he wants to show that it's a great disguise entirely of his own creation... even though it's pretty obviously superfluous, as it seems that no one recognizes him anyhow.