Yu-Gi-Oh!'s Joey Wheeler is one of the anime's most notable duelists, from his humble beginnings with a deck made entirely of monster cards, to much more balanced and powerful decks in later seasons. But of those later decks, a trend and theme began to emerge; while not as harmonious as an archetypal deck, nor as powerful as one centering around a specific creature, Joey's luck-based deck-support came to be a hallmark of his particular style -- but did it actually promote gambling? Not only does Joey's presentation in the series potentially play into real-world stereotypes, but in-universe, his deck is good at passively insulting his opponents as well!
In the Yu-Gi-Oh! anime, Joey is something of a character foil for Seto Kaiba. Where Kaiba is rich, powerful, passive-aggressively polite and uses his privilege freely, Joey is poor, relatively insignificant in non-dueling matters and just plain aggressive, but also surprisingly considerate of others, often offering friendly advice and friendship to fallen opponents.
While Joey originally started out as a bully, when Yugi, his bullying victim, stood up for him, he decided to change his tune -- if not his penchant for resorting to physical violence to solve problems. One could argue that Joey's aggressiveness is just him lashing out over his worries about his ailing sister, Serenity, whom he loves very dearly. And it's here where some of the more... problematic aspects of Joey's luck-of-the-(literal)-draw deck comes in.
Joey's original motivation for joining Pegasus's Duelist Kingdom was to win money so that he could fund his sister's eyesight-saving surgery. Though his luck-based deck is a legitimate one -- and could probably win many real-life tournaments -- and his motives pure, the idea of him gambling his way to victory has some unfortunate implications. It falls into stereotyping both him and the "working-class" he represents as having to resort to skill-less tactics in order to get ahead, always looking for the shortcut or falling for the get-rich-quick scheme rather than working their way up using their talents and determination.
Gambling is by no means a positive thing, as most lose much more than they gain, and gambling addictions are too close to reality for many who, like Joey, may be hoping to win so that they can fund life-saving procedures, or even so that they can spend the money on friends and family as a way to demonstrate how much they care.
But, unfortunate implications aside, Joey's odds of winning are much better than a real-life gamblers, as he often plays his cards together in ways that allow him to make the most of the luck he has; by playing spell-card Graceful Dice (which ups his monster's attack) and trap-card Skull Dice (which lowers his opponent's) together, he significantly increases his chances of winning the battle phase, while also being able to hold one card in reserve should he get lucky with the other.
Similarly, his earliest combo and example of luck-based tactics comes in the form of Time Wizard and Baby Dragon, where Time Wizard's ability to age all monsters on the field and turn Baby Dragon into Thousand Dragon have saved his butt more than once -- which means while there's a one to three ratio of all his monsters being destroyed, really, it's a 50/50 chance of winning.
As a result of not only relying on luck (a factor that tends to upset cheating opponents who are pretending to be psychic -- yes, there's more than one), but choosing high-risk, high-reward situations, Joey's deck insults his opponents as well. Opponents who are new to Joey and his signature dueling style can easily misinterpret his reliance on luck-based cards as him saying "I'm so good at this game, I decided only random chance would allow me to be challenged" -- which as we all know, is completely untrue.
Conversely, they could see it as him delegitimizing strategies and well thought-out combos in general, which can be just as insulting, as duelists spend a lot of time crafting the perfect deck for their play style. Not only does his reliance on random chance insult the opponent's deck, but also their skill, making any win gotten from a luck-based card harder to accept, as it feels... unfair. They could literally repeat the exact same duel, card for card, and just based on the results of one card like Roulette Spider, the battle could have an entirely different outcome.
Overall, Joey Wheeler's delinquent nature, coupled with his focus on gambling-based cards makes him a pain to duel, and might be uncomfortable to watch for those affected by real-world losses. Fortunately though, in the Yu-Gi-Oh! universe, having faith in the "Heart of the Cards" usually works out in Joey's favor... just, maybe don't try it in real life.