Both bitcoin and gold is a good investment, but gold is more stable and more suitable for a long term, while bitcoin is more suitable for short term, and real reason to hold bitcoin is to beat inflation, as we know if we invest our money in fiat then every year our investment value is going down but bitcoin wont be influence by inflation
There is absence of inflation when it comes to investing money in bitcoins and even the price of bitcoin keeps on appreciating over a period of time and that makes it really attractive investment and you can also get benefits from it in short term which is totally missing in gold.
Gold is another story in terms of short term investment because gold is not like bitcoin that you can use in different scenarios like buying items or use it as a money in trading, you can't do that with gold so gold is lacking of volatility. Bitcoin and gold are best for both long term investment because they always go up in price while bitcoin can also good for short term which bitcoin makes very attractive other people who want fast profit scheme.