What you have described is a classical example of gambling and not trading. Anyone willing to risk 100% of their capital in a single trade is more or less saying he is willing to lose all the funds if the trade go bad and which is mostly the case for such type of traders because they don't have the mental readiness to manage their capital properly. This class of people does not last long in trading because the market will always find time to deal with them and make them learn the hard way. You will therefore, agree with me that it is bad habit to risk 100% of your capital in a single trade.
This strategy is used by beginners who have only a few bucks on their balance sheet and for whom it makes no sense to adhere to the risk management strategy, since they essentially have too small a deposit. And they, like in a casino, bet their dollar with a leverage of x100 and in this case they either get a profit of $100 or lose their dollar.