Investing clearly requires risk. So if you can invest what you can afford to lose, that’s fine. But if you can invest more than what you can afford to lose, much better, because that only means you are attracting excellent returns when your investment pays off. And in an investment like bitcoin where hodling alone guarantees secured profits, seeing bitcoin price is still capable to reach its new all time high, then it’s never a waste of time and money if you can invest even on an amount you can’t afford losing.
Your advice of investing an amount you can't afford to lose is not suitable for me and I don't think is reasonable owing to the fact that the Bitcoin investment is not completely risk free and investing an amount you can't afford to lose means that you are investing above your risk which can cause emotional traumatization and anxiety, no body can ever stay calm with the Bitcoin ups and downs if they invested an amount that they can't afford to lose, invest what you can afford to lose to enable you stay calmly and watch the investment grow and that isy opinion on this.