To be fair, 'try the platform out' to me includes getting an understanding of dependencies and configuration. Docker is useful for a lot of things, but even if I want to use containerization in prod, I'd prefer to build my own containers rather than being dependent on someone else's runtime environment, so getting hands-on with the setup is important to me.
If the goal is just to test the application functionality, a demo site that's already set up and publicly accessible would be much easier than having to deploy a Docker container.
In terms of Nginx, using it to handle web server functionality, and especially encryption, while acting as a gateway into your containerized apps is a pretty bog-standard approach, and makes for good separation of concerns. I don't see much value in having that stuff implemented separately within each application and creating more config complexity for sysadmin work.