As far as the routing layer, that's going to be a very small gain as it's all handled by the kernel via iptables anyway. What you give up by using a DaemonSet is a constant overhead for every single worker node that gets created. You have to set aside capacity for traffic you might not have.

A Deployment can be scaled by actual utilization of the pod, and in the near future (if not already) via custom metrics of your own design (e.g. prometheus).

So if you have to spin up 50 new nodes to handle some batch machine learning work, you're going to wastefully create 50 new nginx instances when there's no new ingress traffic to handle. With a deployment, it just scales naturally as needed. So it's not about the marginal gains, it's about using the right tool for the job. :-)