This grouping convention reminds me a lot of Better Specs from the Ruby world:
With rspec, you use the describe and context keywords.
At one level, yes, it's mainly syntactical sugar. As the test-writer, the two approaches may seem interchangeable.
Where I find it really helps is when I'm not the test-writer but rather I'm reviewing another developer's tests, say in PR. I find this syntax and hierarchy produces a much more coherent test suite and makes it easier for me to twig different use cases and test quality generally.