Martinfail is never recommended to players, but those who are new in gambling and think they can outsmart the casino by methods written on the internet which have constraints that cannot be fulfilled in reality. They forget that the casino is running for years and have been making profits for many years too from the players who lose more than win.
Martingale doesn't always fail though and I am living proof of that. It's a useless strategy in the long-term and will suck up your bankroll quickly, but it's actually pretty effective in the short-term if you play smartly.
For example, Rollbit duel arena is a good place to execute this strategy in the short-term thanks to zero house edge.