Square just put Bitcoin checkout in front of ~4 million U.S. merchants. Jack Dorsey's Square has finished rolling out Bitcoin payments via the Lightning Network to its network of about four million eligible merchants across the United States. Customers pay with a compatible wallet in seconds. Merchants get dollars by default — or they can choose to hold Bitcoin, and auto-convert up to 50% of sales into BTC. The push has a clear incentive: Square is waiving fees through 2026. After that, the fee is 1%. The catch: this is still a rollout, not a guarantee of usage. Four million merchants can now take Bitcoin — but how many customers actually pay with it is the number that matters next. Still, the direction is unmistakable. Bitcoin just went from an investment on a balance sheet to a payment option at the till — at millions of checkouts at once. Bitcoin is trading near $73,840, down about 1.3% in 24 hours.