When you're designing a codec or some image processing pipeline, having a human in the loop is great. Designing codecs to have human-acceptable artefacts is as much art as science. Otherwise you end up like Xerox that had scanners which tended to compress "6" as "8", since they looked close-enough to their compression algorithm[1]
[1]: http://dkriesel.com/en/blog/2013/0802_xerox-workcentres_are_...