My problem with these high transaction fees, is that customers naturally wants to minimize expenses, so if they choose to make payments with bitcoin, then they will want to exchange it at the exact rate of USD. So the seller bears the cost of the high fees alone, which may lead to selling at a loss.
Bitcoin payment is optional, buyers should be responsible for the transaction fee, not you. If they do not want to pay with bitcoin, they can use fiat.
If you use exchange like binance the easier way would have been using your pay or user ID but this also depends on the use to have same exchange and probably funds from it. So you can just add that too that People with the exchange can use that. But as you know the issue of centralized exchanges like this do not leave off your funds on them for long. Once they get to some quite significant amount you can withdraw them to your wallet. At least it will minimize the transaction fee
What if you use an exchange and a customer pay you and Binance freeze the coin and said that it is tainted? Even if the coin is later released, it would have been a difficult time and it is going to stress you out to get your coins. Bitcoin gives the freedom not to depend on any central organization.
Many payment processors will charge you a percent of a transaction, like 1%. Even PayPal will do so.
I think this will depend from country to country. Like in my country, local bank transactions are of very low fee, most do not require fee, but with little monthly charge. There are online microfinance banks and fintech with zero transaction fees, or zero transaction fee for certain number of transactions in a month, with not monthly charge.
I was thrilled 3 weeks ago when I wanted to fund a newly opened trading account with an Australian broker. The broker offers "Binance pay" and the transaction was fast, free and seamless. That's what we need this time, not only the LN, though it's also a good development, but still with its issues.
Binance Pay will encourage centralization and dependence on centralized authority. For this kind of shopping, lightning network has not two reasons it was created than this, to be able to spend bitcoin with cheaper fee and faster within a second or few seconds.