Not to overcomplicate things right now it's basically because it is a good investment, it has a good liquidity and has been supported and trusted by the crypto community. As long as the crypto community believes in bitcoin it will constantly go to higher price, bitcoin has solidified its position in cryptocurrencies without market making and it is impressive how its been supported all these with so many projects going here and there.
Bitcoins DLT became popular and still getting some attention, blockchain technology really is one of the main reason to buy bitcoin, you don't have to use it because others will, and as long as it is being demanded its value will never fade away and will continuously grow, that's why its always a great investment.