Signs that Amazon might venture into cryptocurrency appeared to help drive bitcoin’s price sharply higher Monday, pushing the coin toward $40,000 only days after it fell below $30,000. While the crypto market seemed cheered by the prospect of an Amazon crypto initiative, which would represent another mainstream seal of approval for digital money, it revives questions about the essential role of the cryptocurrency.

For some time now, a key selling point among bitcoin backers has been the coin’s potential as a safe harbor against inflation and other developments in conventional markets. Yet the inflation hedge has largely failed to pan out, as reflected by last week’s poor market performance for bitcoin amid inflationary signals.