If you could only invest in one, I'd say gold. As much as I love Bitcoin, its a technology in its infancy, theres no telling if its going to last long term. I think your chances of having a high return are greater with Bitcoin, however you are pretty much guarenteed at the very least some return on gold. Gold has been currency/an asset for 5,000 years. Bitcoin has been for 6 years.
If its not a one or the other choice, why not invest in both?
So you do not believe that Gold will become less valuable in hmmmm maybe 15 years time?
Do you think it will be as valuable as Bitcoin? Or much lesser in value as Bitcoin?