This is another wrong phrase for bitcoin long term investment. It belong to gambling because in bitcoin long term investment, we are not investing to lose money even though we are putting in part of our discretionary income. I will not diligently put at least 20% of my income into bitcoin and kept for my retirement and partly to hand over to my heirs only to lose them. Bitcoin is not disappearing anytime soon or turning into zero so the chances of this me losing my money is very slim or non existent.
You can consider your Bitcoin investment is for long term, and for profit but life is always hard since your birthday. You cried at a first time you were born and I'd like to use it metaphorically on how life is very tough for everyone, not only you.
So investment adventure with Bitcoin is tough, and you must afford to lose your money even you consider it as your long term investment into a kind of very safe asset. I agree that Bitcoin is a very good investment asset, safe enough but I disagree to consider risk for your investment portfolio is nearly zero. Risk truly exists and you can not eliminate it only by your belief.
Risk is definitely present in everything, and this risk can never be ignored. Similarly, you must accept the potential risks involved in Bitcoin investment, and prepare yourself to tolerate that risk before investing. Bitcoin will never guarantee us profits, no matter how positive Bitcoin's potential is, so you must invest in Bitcoin with an amount of money that you can tolerate these risks, and in Bitcoin investment, you must invest for the long term.