Why would you need to render the content from Drupal’s block layout via a node template file? Normally, that is the territory of page templates. The use-case for me was a page where node-specific fields were mixed in with blocks to the extent that rendering region content in a page template file wasn't going to work.
I needed to be able to render my region content amidst field values in my node template files. Drupal doesn't let you do that out-of-the-box.