Because if you really believe that it will be worth (much) more in the end, it's not even doubling down, it's just getting bargain buy-in prices. Unfortunately, you first have to believe, and to believe, you have to understand; so if you just blindly follow someone's advice you are destined to doubt, fear, and consequential losses. That's why I would not recommend for OP to ever buy bitcoin as an investment before (s)he understands.