Yep. RAD Game Tools (where the author works) combines "within-the-GPU compression" with content compression to make them work better together. They have a texture compressor that not only has high visual quality, but also sets up the fixed-rate block-compressed file more likely to end up smaller compared to other encoders when the file is additionally put through general purpose DEFLATE/ZSTD file compression. And, then they have a general purpose file compressor that has higher size/speed performance as well. Win + Win.