A common use case when developing Django templates is rendering a block only when the block has content. Take this for example:
If you use blocks as designed out of the box, you’ll end up with some extra markup that you may need to hide via other methods (such as CSS). That’s definitely not ideal.
The tag captures the content of the block to a variable within the template which can then be tested for existence, allowing you to conditionally show the block depending on the contents.
Using the tag is as simple as this:
Hopefully Django adds this in the future.