Internal HTTPS vs TLS termination question

I see Traefik can do TLS termination, which is great, but does that mean I don't have to use TLS for communication between containers as well since the Docker network is already encrypted?

Or is it a good idea to use TLS for everything anyway?

Is there any example of a config for using Traefik for TLS with a single cert, but then also having communications between Traefik and other containers use self signed certs as well?