As already clarified in other FAQs, the enablement status on the e-invoice portal doesn’t mean that a taxpayer is legally obligated to do e-invoicing. The ‘enablement’ was to primarily ensure only the taxpayers having notified turnover limits (and not any taxpayer at their option) can register and test/report invoices on the trial portal / IRP.
The listing of enabled GSTINs was solely based on the turnover criteria of GSTR-3B, as reported to GST System. So, it may contain those entities, depending on the facts of a case, to whom e-invoicing might not be applicable for some reason. Thus, it is for a concerned taxpayer (both Buyers and Suppliers) to confirm fulfilment or otherwise of conditions as per notification/rules.