GCP Kube-Lego forwarding rule pricing

Question

I've started to use kube-lego to manage load-balancing through a nginx controller, instead of GCP Load Balancer controller.

I am being charged for: Network Load Balancing: Forwarding Rule Minimum Service Charge in EMEA right now, at about 21$ per month.

Isn't the load balancing supposed to be done by nginx? I have TCP Load Balancer in my GCP network resources.

Isn't possible to send the traffic to a node port and do the load balancing on the nginx controller instead ?

I thought the advantage of having a Nginx load balancer would avoid creating a load balancer on GCP and thus avoiding paying crazy expansive network resources.

What is the purpose of the nginx controller then? Beside maybe automatic certificate renewal with LE.