For me reasons not to invest in crypto are if you don't have any idea what crypto is, lack of ineterest to learn crypto market and investment, impatient these are tje most common reason why you should not invest in crypto as we are know crypto is very high risk and volatility but if you know what you are investing for, the profit here is also greater than investing in any other stock market.
Of course, if you look for certain projects that give you bonuses on time that will increase your income in the future, then definitely there is a sense of such activity. But if it concerns not real business, but crypto-currencies, then risks are assumed everywhere and constantly.