The article glosses over a few distinctions for sake of brevity. There is a difference between “intermediate process step” and “intermediate file format”.
She used the word “intermediate” to represent a workflow step, for which any number of file formats could be acceptable depending on quality requirements. Her article chose to focus on lossless formats because they have the highest quality. So that’s technically described as a “lossless format for the intermediate step”.
But a true “intermediate file format” (also called mezzanine format in some places) is only visually lossless, which means some color information that the eye can’t detect (even after a pretty hard color grade) is thrown away to get file sizes down, and the decompression algorithm is optimized for speed to make editing smoother. These formats (with ProRes and DNxHR being examples) are frequently used in studios for speed and space reasons. For most practical purposes, they are indistinguishable from a true lossless file. They are also popular because lossless files have a tendency to not play back fast enough at 4K.
The Shotcut export presets are properly categorized by whether they are truly lossless (mathematically bit-for-bit exact) or visually lossless (technically lossy, but undetectable change to the human eye).
One other note… if your videos are screencasts, you might find these two presets useful when ready for the final export. The file sizes are ridiculously small: