Render didn't support Docker images last I checked, and the worst part of Heroku and cloning it was not actually having a locally reproducible build image. I want to deploy what I've built locally, not hand my source over to some magical pipeline.
Different strokes. Personally I avoid Docker in favor of source-code-deployment; the "magical pipeline" is usually just "git pull and then run a provided command". But Render does support Dockerfiles for eg. installing a runtime like Deno that isn't provided out of the box
