I knew a guy who was absolutely terrible at money management, he bought Ether with money he had saved for vacations. He ate poorly and didn't buy clothes to make this investment, after which cryptocurrencies fell in price. This example is also great for betting and gambling, I think everyone knows guys who bet with their salary and then complain that prices in stores have risen so much that it is impossible to live normally. You need to take care of yourself in the future, because we will all end up there. You need to be able to save money, or bet only with extra funds.
What a terrible example you have here mate, comparing your friends investment in cryptocurrency to gambling in the basis of their risks, you should have differentiate both in terms of risk factors let say for your friend investment in Ethereum is an assets and he did not lose until he decided to sell at a price lower than he bought it, but if it gambling, once you lose, 100% of your money is gone without any remedy to restate your money.