Unfortunatelly stone/paper/scissor is 100%luck/0%skill game
There is no luck in stone/paper/scissor in the sense of randomness, which is what has to be eliminated to make it legal for coin games.
The outcome of a stone/paper/scissor game is fully determined by what each player is doing.
still there is no skill needed, as every "strategy" is as good as any other, all you do is gamble