It doesn't relate at all, two completely different things. You're referring to Eclair wallet, btcpay is a full node that has LN implementation on top.
You can get payments from eclair wallet in your shop if that's your concern.
ok, so are they saying that BTCPayServer - a payment gateway responsible for matching eshop purchases to LN invoices - can be integrated with c-lightning or LND node for keeping the funds that go through the gateway, and also for reading info about LN transactions. But they don't yet support integration with other two nodes. Is that understanding correct?