An internal gRPC update invoice endpoint would allow us to push invoice updates to LNDhub, where the current implementation pulls them from LND. I think a push mechanism would allow us to scale LNDhub more easily (multiple instances), and it would also allow for more flexibility in the choice of node backend (something like a SubscribeInvoices interface would no longer be necessary).
An internal gRPC update invoice endpoint would allow us to push invoice updates to LNDhub, where the current implementation pulls them from LND. I think a push mechanism would allow us to scale LNDhub more easily (multiple instances), and it would also allow for more flexibility in the choice of node backend (something like a SubscribeInvoices interface would no longer be necessary).