Well, to be fair, it does exist in dice game. You can set it like this
and voila, you have a 50-50 probability of losing or winning.
Your win is going to be a little smaller than what you bet, due to the house edge, but the probability of it will be exactly 50%.Logically, as I think of it, it does exist in all gambling games.
. 50-50, it is either you win or you lose in a bet. But it is more complicated on the technical side, since, for that, we need to calculate the probability or the chance of winning. So somehow Titangel claim of 50-50 slots is logically right(you win or lose) but then technically unsupported.~
And still I think you can't apply 50-50 term to slots, because there are cases when you get back, say, $0.8 out of your $1 bet. Is it winning or losing? Such things never happen in dice, where you either win at least a little bit, or you lose your whole bet. You can't "win" just a part of it, or your whole bet(1x multiplier) back in dice. That's why dice can be called win-or-lose, or 50-50, game, to some extent, but slots can't because there is a possibility of a draw, so to speak.