People propose wildcard moves for Rock Paper Scissors with the best intentions. "Dynamite" is the most common. It's supposed to beat Rock and Scissors, lose to Paper, and create more variety. What it actually creates is a game where Paper wins too often, everyone switches to Paper, and the person who realizes this first wins every match until everyone else catches up. At which point you're back to playing Paper Paper Paper in an endless tie loop. The game is broken.
The reason standard Rock Paper Scissors works is mathematical. It's a nontransitive cycle: each throw beats one option and loses to one. No move dominates. The Nash Equilibrium — the theoretically optimal strategy — is to randomize equally across all three. If you deviate from that distribution, an observant opponent can exploit you. The game rewards balance and punishes predictability, and it does this without any move having a structural advantage over the others.
A wildcard breaks this the moment it has unequal win/loss ratios. "Dynamite" beats two things and loses to one. That's not balance. That's a dominant strategy with a single counter. Rational players converge on Paper (the Dynamite counter) and you're playing a two-move game — or everyone uses Dynamite and you're playing rock paper scissors plus a lot of ties with one specific resolution mechanic.
The right way to add variety, if you want to, is through balanced expansion: every new move must beat exactly as many throws as it loses to, and the total number of moves must be odd. Rock Paper Scissors Lizard Spock does this correctly. Five throws, each one beats two and loses to two. The Nash Equilibrium shifts from one-third each to one-fifth each, but the structure holds. No move dominates. You can't just spam Spock.
Casual games can use whatever rules the group agrees to, and if everyone has fun with house rules, that's fine. But the "Dynamite" scenario typically ends with exactly the argument it was designed to avoid: two people standing around disputing whether the wildcard they just invented actually works the way they thought it would, which is why there's a rulebook in the first place.
The WRPSA only sanctions Rock, Paper, and Scissors in competition. That's not conservatism for its own sake. It's the recognition that the three-move structure is the reason the game is fair, and fair is what makes winning mean something.