Bitcoin is a very volatile process. No one can accurately say whether the price it is going to be at today will be the same price tomorrow. No matter how close a friend I am at work, I don't tell anyone to invest in Bitcoin. If the price they bought it at today drops tomorrow, they will think I cheated them. I cheated them out of their money. In that case, I will fail to convince them that if they hold it for a long time, its price will increase much, much more.