Bitcoin is now on by default at Square checkouts across the U.S. Sellers don't have to apply. Square switched it on for every eligible business, whether the owner has ever thought about bitcoin or not. The customer scans a QR code with any Lightning wallet and the payment settles in seconds. The seller gets dollars by default or can choose to keep the bitcoin, and there are no chargebacks. Sellers can also auto-convert up to 50% of their daily card sales into bitcoin. The limits: $600 max per payment, $20,000 a day, and sellers in New York are left out. The fee is 0% through Dec. 31, then a flat 1%. A card tap on Square's free plan costs the merchant 2.6% plus 15 cents.