[SahAssar]

I think most nginx deployments only do web, but the article on mail functionality does outline some of the reasons: https://docs.nginx.com/nginx/admin-guide/mail-proxy/mail-pro...

Besides those listed I think a plus would be to only have one server listening on priviliged ports (<1024), using the same/similar TLS configuration for both web and mail, etc. Basically having one service be the arbiter of your incoming traffic and its encryption.

Some people also throw dns via DoH/DoT in: https://www.f5.com/company/blog/nginx/using-nginx-as-dot-doh...