Static Configuration: File & Environment variables - Why mutually exclusive?

Traefik Traefik v2 (latest)
1

According to the documentation, it's not possible to use both a (static) configuration file as well as environment variables alongside each other (same goes for command line arguments).

I think I'm not the only one if I say that I want the majority of my configuration in a file and put more important information (e.g. secrets) in environment variables.

Example:

Having a static configuration, without acme email address.

api:
  dashboard: false

log:
  level: INFO

entryPoints:
  web:
    address: :80
    http:
      redirections:
        entryPoint:
          to: websecure

  websecure:
    address: :443
    forwardedHeaders:
      trustedIPs:
        - "172.17.0.0/16"
        - "173.245.48.0/20"
        - "103.21.244.0/22"
        - "103.22.200.0/22"
        - "103.31.4.0/22"
        - "141.101.64.0/18"
        - "108.162.192.0/18"
        - "190.93.240.0/20"
        - "188.114.96.0/20"
        - "197.234.240.0/22"
        - "198.41.128.0/17"
        - "162.158.0.0/15"
        - "104.16.0.0/13"
        - "104.24.0.0/14"
        - "172.64.0.0/13"
        - "131.0.72.0/22"
        - "2400:cb00::/32"
        - "2606:4700::/32"
        - "2803:f800::/32"
        - "2405:b500::/32"
        - "2405:8100::/32"
        - "2a06:98c0::/29"
        - "2c0f:f248::/32"

providers:
  docker:
    endpoint: "unix:///var/run/docker.sock"
    exposedByDefault: false
    watch: true
    network: proxy
  file:
    directory: /dynamic

certificatesResolvers:
  myresolver:
    acme:
      storage: /certs/acme.json
      dnsChallenge:
        provider: cloudflare
        delayBeforeCheck: 15
        resolvers:
          - "1.1.1.1:53"
          - "1.0.0.1:53"

And provide the email separately through environment variable:

TRAEFIK_CERTIFICATESRESOLVERS_MYRESOLVER_ACME_EMAIL="admin@example.com"

So while it's not possible, my question is why? Why is it mutually exclusive? What's the (design/techincal) reason behind this decision? And will it ever be possible to use them interwined?