I don't get it. Progressive JPEGs have no redundant information - I verified that - and are usually a bit smaller than sequential ones because of a more favorab

I don't get it. Progressive JPEGs have no redundant information - I verified that - and are usually a bit smaller than sequential ones because of a more favorable arrangement of different components for entropy coding. And producing initially blurry images of text is not the fault of progressive JPEGs but at most a bad technology choice for a given use case. The image will get fully loaded in the same time no matter if it is sequentially or progressively encode so at best a sequential JPEG containing text can claim that the first lines get readable earlier.