This is not exactly true. The all in strategy is indeed risky, but it is actually really effective in beating the house in the short term as long as luck sides with you since it's impossible to beat the house in the long run.
Everything in gambling comes with a layer of risk compulsorily which is why you should always invest only what you are willing to lose when dealing with any strategy.
This all-in strategy works sometimes and when it works, it brings very good results and profits but you know that life is unpredictable. That's why I considered all-in strategy contains very high risk and with me, defending my initial capital must be the biggest priority. Therefore, I don't take high risk from any all-in strategy, as I know when it fails, I will lose very big fund.
It is the same principle and discipline I use and try to maintain in both investment, trading and gambling.