I might not be wrong if I compare Bitcoin to business. In trading, the price of a product is not always the same, the trader has to buy and sell according to the price of the product so that he does not face loss. With that in mind, I liken Bitcoin to business. Bitcoin goes up/down in value just like a trading commodity. Which will expose you to both profit and loss.Since your friend told you about the profit of Bitcoin, the formula should have also highlighted the downside. There are both pros and cons to investing in buying and selling Bitcoins.
One more thing, it is very important to be careful about your wealth. Otherwise you may face a great danger.