Again, you're confused about what "legal tender" is.
It is up to sellers to decide what form of payment they accept. It is perfectly legal for a seller to accept only a form of electronic payment, or only certain sizes of bank notes, or payment in bitcoin or blueberries or bubblegum. This is all totally fine and has nothing at all to do with the concept of legal tender.
Legal tender is simply what kind of payment must be accepted for the settlement of a monetary debt. If you owe your bank $1,000 as an overdraft, the bank is required to accept repayment of that debt in U.S. currency. It cannot require another form of payment; meaning if it refuses U.S. currency then tries to sue you, the court will find that the debt has been satisfied. In practical terms, this never happens.
