After tumbling some 70 percent from its peak, bitcoin is reaching a point where even an authority like Mohamed El-Erian thinks it could be a buy.

The chief economic advisor at Allianz, considered one of the most influential financial market thinkers in the world, said Friday that the cryptocurrency would be worth considering if it falls before $5,000. Bitcoin was trading around $5,870 as El-Erian made his remarks on CNBC's "Squawk Box."

"I don't think you get all the way back to $20,000, but I do think that you need to establish a base whereby the people who really believe in the future of bitcoin consolidate and then that provides you a lift," he said.

Bitcoin saw a meteoric rise in 2017 as digital currencies surged in popularity and dozens of competitors came to market.

However, a number of obstacles, from continued stories of fraud to threats of a regulatory hammer coming down across the world, has caused a big pullback since a December price peak of more than $19,000.

Now, the question turns to what is the future of cryptos and the shape that bitcoin and others will take. Where at one point there were more than 40 digital currencies with market caps above $100 billion, bitcoin now alone holds that designation, according to CoinMarketCap.

El-Erian said cryptocurrencies likely won't be currencies at all but more like commodities.

"I suspect that if you look 10 to 15 years down the road, we will have digital currencies but the public sector will have involvement in that. It will not be pure bitcoin," he said. "But the blockchain technology, take that seriously."

Blockchain is the foundation of bitcoin, serving as a digital ledger of financial transactions and is expected to be used widely in banking and other sectors in the future. Bitcoin will exist alongside that technology but perhaps not as its advocates anticipate.

"It will be a means of exchange," El-Erian said. "It's not going to be a currency, it's going to be another commodity-like asset out there that you can trade, and mainly as a store of value."

Bitcoin's price was slightly higher Friday morning and off its highs for the day.