When I was experimenting with this it didn’t seem like you had to distribute the cert to the service itself. As long as the internal service was an https port. The certificate management was still happening on the proxy.
The trick was more getting the host names right and targeting the proxy for the hostname resolution.
Either way IP addresses are much easier but it is nice to observe a stream being completely passed through. I’m sure it takes a load off the proxy and stabilizes connections.