The latest tumble leaves bitcoin more than 40 percent down from the record highs of around $20,000 reached in mid-December.
Buffett's comments come a day after JPMorgan & Chase Chief Executive Jamie Dimon said he regrets calling bitcoin a fraud.
There have been public complaints that Israeli banks were making it difficult for some customers to transfer money from their accounts to buy bitcoin.
These days, newspapers and websites are full of stories about cryptocurrencies, virtual currencies, and bitcoins. Confused? Here is a ‘guide for the perplexed.'