Both of them are useful in a certain situation but the good thing about Gold, the price never drops like Bitcoin. This makes people become certain that investing in Gold is a better option than Bitcoin. But those who love to take risks will choose Bitcoin as well as they believe that despite the high risk, it gives them more profit.
If we think which of the two will seemingly stay long and for several decades, we can assure that Gold remains while Bitcoin is uncertain.
But of course, it depends on our preference and risk appetite. But for me, I'd choose them both because they are both profitable.
Looking back, we have seen Gold prices decrease in 1980-2000 and 2011-2015. This is completely normal because Gold prices had increased very strongly before that. The same thing happens with BTC: after each strong uptrend of +1000-2000%, BTC price often has a downtrend of -70-80%, and I think this is a part of the market. We cannot have high profits without accepting sharp declines. It is the large volatility that can create large profits for investors who understand the cyclical nature of the market.
For professional investors, or at least those who think they are truly professional, investing in BTC at this time around the Halving is a quite wise decision because we will soon have a strong uptrend and high profits, something that Gold is unlikely to achieve because Gold marketcap is too large.
Due to its increasing price, Bitcoin has become increasingly attractive to investors. Investors are interested in profiting from the difference in bitcoin prices by holding them for some time. Bitcoin is different from gold because gold tends to be stable and doesn't move quickly like Bitcoin. People who don't want to speculate may prefer gold to Bitcoin because they fear its rapid movements.
However, to last a long time, gold and bitcoin can last a long time. Many people want to hold physical form, so many choose gold over bitcoin. However, with the popularity of Bitcoin now, some of them also want to invest in Bitcoin. The type of investment will depend on each investor. If investors are willing to open themselves up to accepting new things like Bitcoin, they will accept Bitcoin as another investment besides gold. Moreover, this is about how they can gain profits in the future.