You have a point investing all of money in crypto currency is a big risk that you will putting your money in a not sure platform of investment wheather it will gain profit or it will loss but the main reason is if the people who investing in crypto currency have knowledge of how crypto currency works because some people are just investing their money without a knowledge of what totally bitcoin is thats why they lost their money investing to it. So I prefer to all of investors in crypto currency to gain more knowledge about it before putting their money to crypto.
Personally, putting all your money in a cryptocurrency investment or bitcoin investment is a big mistake for a reason that not all the platforms of invesment in here is a sure win. It is a high risk to take because if ever that the investment will fail then what is your back up and saved money? It is still a safe play when you don't invest all you got.