From my own experience, I have been able to double my bitcoin more often than I hit a losing streak and lose everything. Definitely not fail safe, but that is a bit less risky to me than regular martingale.
Any strategy that doubles more often than it busts is a winning strategy. You've almost certainly either been lucky or have mis-counted.
Well it hasn't been a winning strategy for me, because when I hit that eventual losing streak, it doesn't matter how many times I've doubled my funds, because it goes back to zero.
To your point, perhaps it has involved luck, but I don't think it's very odd for people to double their money before losing it all when following martingale.