Back in the day I was rolling my own payment processing and it was extremely simple, efficient, and safe - pre-generate a bunch of cold addresses and hand them out to buyers.
Why did you do that? Why can't you just have a BTCPay Server installed and let it undertake your invoices automatically?
This was years before BTCPay existed. Still works fine.
None of this is feasible with LN
Let me correct you; it's a far more efficient way to transact than to update a ledger written in hundreds of thousands of hard drives.
Not from a merchant's POV. There is more hassle involved in receiving LN payments for no tangible benefit.