When you are all-in anything, it is bad as it is basically very risky and if you have an all-in habit, you can are already in a very bad direction and must change it as soon as possible before it's too late. Prevention is better than cure, and change your all-in habit and practice are better than waiting for losing all money and want to start your second life, it's won't be easy at all.
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.