Invest your 20k in gold because its too much to invest in bitcoin. If bitcoin fails then you lose your 20k and thats not what you want to happen. Gold will keep value so your money will be kept safe probably even more safe than a regular bank.
20k usd is not a big amount of money to invest in the bitcoin. The gold price will rise slower than the bitcoin.
True gold might rise on future too but still it's slower compared to Bitcoin but in gold you could assure making profits on Long term but if you like to see profits on short time or on couple of years then it's fine to invest in Bitcoin but remember the risk involved on it.
You have a point Bitcoins price increase or movements is more higher compared to gold but if i have the money I. Would really invest in both since I could somewhat assure that these would surely rise up on long term or upcoming years. Yes it may have risk but it's a normal thing in investments.
For me, I have only an ample amount of money to invest in, I would prefer to invest on Bitcoin because I see the potential that this would give me good profits in the future. And also I'm doing all coin trading at the same time. On op he should diversify his money so that he would make more source of income in the long run.