For the record, legal tender doesn't mean what you seem to think it means: legal tender is that which
must be acceptable for payment of a debt. In Scotland, for example, only coins are legal tender. For a regular sale, the merchant is free to accept or reject whatever they choose. But the law on legal tender is designed to prevent bad lenders from keeping debtors on their books by not letting them discharge their debt.
Take a tenant in a secured tenancy, for example. They try to pay their rent, but the landlord won't accept payment, because they want an excuse to evict them (non-payment of rent being one of the few acceptable reasons for evicting a secured tenant). But if (being in Scotland) the tenant dumps a bag of coins on the counter, they are obliged to accept that to settle the debt.