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.
Yes you are right if you dont have an experience or dont know about crypto currency it is very risky thing you will able to loss your money thats why many people saying learn and invest in crypto currency.
Investing here in crypto does not required since investing here is just like putting your money in a bank account and holding it until such time that it has already profit but if you really don't have the knowledge yet with what you are doing and with the one you are investing at then don't try first until such time you are ready.
I feel the best thing is just to try every means to stay careful and secured in this world. Even in the real world, there are thieves, and those who will not even bat an eyelid about conscience and steal everything from you just in one day, but to stay secured, the only thing you can do is to beef up your security level.
In the digital age, where we now have digital thieves, that is also the only thing you can do as there are so many ways to achieve this and as long as you stay knowledgeable about all the things you need to do to stay secured, then you should be fine.