I'm not currently using any spes. schema to deploy to prod. I just deploy often to prod and fix bug, but I like the deploy to prod, button. I think I will use that.
It's not clear to me how it will behave with regards to resources. I think It would be hard to update env var. I think maybe that would be in the hands of the developer to make sure that is working as it should. But for resources you should have a way of updating the resource to select the correct one. I'm not sure if that would be to select a different resources, or that you have two versions of a resources, a prod resouces and a dev/stage resource that share the same name.