It's wrong that if you don't take risks, you won't make a profit. The risk must be justified, and it is for this reason that risk management must be followed. Otherwise, it will not be a trade, but a casino.
Invest what you can afford to lose, means there is risk in investment. If you are in trading, risk is bigger so there is no risk party and you must know it. Surely everyone want to have profit, that only possibly comes after they already took risk.
It's only difference that how they manage risk and benefit for their investment or trading, and it's very unsafe and also unrealistic by chasing very high profit while risk is not controlled at all. This way, they will only take loss later and not get any profit.
2. All investments has their risks, saying investment have zero risk is very bad because it's wrong, before going into any investment plans you need to wager the risks that follows, this is why many new business collapse for no reason, they want the good part only and are not prepared for the risk part.
Let's say about investment and investors, but ignore business here. Bitcoin has very good ROIs over many years, and with high security of the blockchain, it's super good to own bitcoin, store it safely and have it for your investment portfolio.
No matter how good Bitcoin is as an investment asset, risk exists and you must control risk of your investment portfolio as well as your finance in general, for chasing success and profit with Bitcoin investment.