Gold have thousands of years of track record. And it's a great hedge against inflation. Many will say it's real money. I think everybody should own some gold.
I have no idea if Bitcoin will go up or down. Nobody knows. But just like gold, you should have some.
Like everything, buy low, sell high. If you're not sure if it's cheap, it's because it isn't. Have liquidity and during a crisis (happens more often than people think) use that liquidity to buy assets. Real estate is a good option. Car is a bad one.
Imagine this: You have one BTC and it goes to $5million EACH. Do you wait and hope to go to $10million? Of course not. You sell and buy gold, real estate, stocks, cash, etc and retire. You can keep 0.1 BTC and hope it goes even higher but you already secured your future. It doesn't matter what happens next, you're set.