bitcoin plays a critical role as a fast profit giver
A fast profit giver or a fast value loser, depending on what it feels like doing that hour. If the purpose of some part of a portfolio was a "fast profit giver" all money would be in it and then it would no longer be profitable any more. What you should be saying is that it's high risk, high reward.
Which is better, Bitcoin or Gold and are they even comparable?
Gold has the drawback of being moderately inconvenient to spend and use as money in everyday life. Fiat has the drawback of potentially having broken promises because it is controlled by governments (broken promises like the gold standard).
BTC solves the problem of government control and third parties in digital money, thus creating a monetary system which is both scarce like gold and a currency like fiat. The only problem is that without universal acceptance, this monetary system doesn't work, and BTC is too early in development to be at all practical for this purpose.