In my opinion, both are very profitables, because both of them are valuable and have the most promising potential. Gold is always trusted by people and it will never lose its value, and its price keep growing slowly. BTC however is increasing fastly and expected to become a lot more expensive in the future.
It is indeed that both are profitable. However, holding gold is more safer or you'll feel secured than holding bitcoin. Although bitcoin will definitely let you earn huge profit, it can also make huge profit loss in a short period of time.
Gold may not let you earn huge profit like how bitcoin can, but it can guarantee you that you'll going to earn profit as time goes by. If you have enough funds, it is much better to hold both. But if none, I would rather hold gold for long time investment and bitcoin for a short time investment.
Actually I am holding both for the future. Honestly, I do not trust FIAT. I can not put all trust in the value of FIAT I am using everyday. However, I can not stop to use FIAT and replace it by cryptocurrency or gold. Therefore, I spilit my 80% funds to 6:4 (Bitcoin 6 : Gold 4) to save my money for the future.