Suppose you woke up tomorrow morning and found that Bitcoin had dropped to 0$, or that Bitcoin had disappeared or been scammed. How will you be at that moment?
Isn't that amazing? We can't just buy bitcoin cheaply but we can get bitcoins for free this time lol but seriously I don't think that would happen. Only scam coins can turn to zero but if you look all legit cryptos and altcoins, do see a zero value? I believe none. Sure their value can dump too much adding a lot of zero's on their price tags but still they didn't completely drop into zero.
The same thing can also happen to bitcoin, its price can dump down to 20k, 10k, or even 3k but it won't hit zero because many people are buying and taking advantage of the dip which results for the price to recover and pump. You can get scammed and your bitcoins can be stole in your possessions, that's the only thing that can happen to you if you will not guard your bitcoins properly.