Warren Buffett appears to have a good working relationship with banks. Endorsing bitcoin or crypto currencies could jeopardize that relationship.
There's a simpler explanation.
Look at what Buffett says about gold:
(Gold) gets dug out of the ground in Africa, or someplace. Then we melt it down, dig another hole, bury it again and pay people to stand around guarding it. It has no utility. Anyone watching from Mars would be scratching their head.
Then compare that to
what he says about cryptocurrencies:
"Cryptocurrencies basically have no value," he said. "You can't do anything with it except sell it to somebody else."
There's no need for a conspiracy theory involving banks. He doesn't see value in speculative store-of-value assets like Bitcoin and gold. He's primarily a stock investor looking for predictable returns on investment.
He's an old man, stuck in his ways. Let him be.
Warren Buffett's business and livelihood is tied up in US stocks. Asking him to comment on gold, is like asking the largest shareholder of Pepsi their opinion on Coca Cola. Gold and precious metals are something like a competitor to US equity markets. Buffett doesn't want investors to put their money in gold. It translates to less cash being invested in equity markets. That works against his own self interest. He wants investors to buy stocks instead, which increases his own holdings.
Bitcoin is similar to gold being something like a natural competitor to stock markets and banks.
For a billionaire like Warren Buffett, it is important for him to have good connections and a working relationship with the banking industry. He relies on banks to help him move and store money. The better relationship he has with banks, the better rates and terms he gets.
If Buffett came out in support of bitcoin, it could upset the relationship Buffett has with bankers. They could give him worse rates and terms. Or retaliate in some other fashion.
There's no need for conspiracy theories when its simple necessity we're discussing.
