Well, I would agree with you. Bitcoin is a digital asset and there is no guarantee that it will survive for more than a couple of decades at the most. On the other hand, bullion metals such as gold have been in use as investment assets for more than 5,000 years and IMO, it will hold its value as long as the human race exists in this planet. No one said the value of Gold is always high. At the moment, the value of Gold is still high because the world think it is limited supply and rare. Its ability to use in the industry is also very good, almost as it is the best in all metals I know.
Well, holding BTC can make our money grow. Holding GOLD can also make our money increases. Holding land and house, can also make our money increases. They are called investment. The problem is, the price of crypto can go up and down, while GOLD, land, and homes never go down. I never heard that there is a falling land price every year, surely they all always increase every year. So which investment is better? Of course GOLD, land and house. But if you compare it with the increase in the price of crypto, it will be difficult. Because maybe a certain price increase of crypto can be faster and bigger than GOLD. However, everything has its own uniqueness and advantages. That's why there is a term, dont put all your eggs in one basket.