Precious metals have intrinsic value. Crypto has none whatsoever. Further, as Ernie pointed out, there are very low barriers to entry. I don't see the parallel.
People invest in Gold/Silver/Platinum the same way. Rarely do people keep ACTUAL bullion in their house. It's extremely rare.
Precious metals have a barrier to entry, mining or value. Cryptos have a barrier to entry, mining or value.
Mining a cryptoconcurrency takes hardware investment, energy investment, and time. BTC and other cryptos have a set amount of coins possible. BTC has a limit around 23million coins if memory serves correct.
Some cryptos don't have a limit but get their value in other ways.
Gold/Silver/Platinum have a finite amount (on earth) possible.
Cryptos get harder to mine (generally speaking) as time passes and some have a finite amount (depending on design)
They also have value in the fact they are a currency not controlled by a bank or government. The Fed or other governments currencies can be manipulated. The US Government can print more money or not (same for other governments). They can pull levers and manipulate value. Cryptos that cannot be done as no central authority controls them.
I will also add cryptos have value in the fact that each transaction is documented. Additionally, each transaction does not need to clear a bank when dealing with cryptos. Something banks are not to happy about.