BIP: 70 Layer: Applications Title: Payment Protocol
This is a salutary lesson about what not to do.
A. Don't distinguish actors in a peer to peer network.
Providing a facility that differentiates peers into "merchants" and "customers" risks the whole ethos of a P2P network that treats all participants as equals.
B. Don't embed past failures in the new system.
X.509 certification, apart from requiring the centralising services of "authorities," has been a disaster. (https://en.wikipedia.org/wiki/X.509#Security)
With all the cryptography inherent in LNP/BIP, to drag this barbaric relic into the new regime is repugnant. Let it die.