Lots of reasons.
It is hard to imagine how quickly he went from a normal guy to Auschwitz victim, in terms of looks. The pics show that drastic change.
Also, as you have said, to compare the general condition of the body to the autopsy. Before I saw the pictures the autopsy seemed very basic to me. IMO, the pictures confirmed that. It seems the ME just did a basic, down and dirty exam figuring this was some homeless guy. A more thorough autopsy with a conclusive cause of death would have stopped a lot of unneeded speculation about MH. Of course, the ME had no idea there would be so much interest in this guy when he did the exam.
I personally wanted to see the scar. Lots of people were suggesting he had bariatric surgery. I think we can conclusively say that is not the case, now that the photos are released. That is not a scar from bariatrics. (Note, no resectioning of the stomach or intestines was noted in the autopsy). It also was not super recent. Definitely a surgery he had as an adult, but probably years before he went on walkabout.
The penis stuff is interesting. Starvation victims sometimes self mutilate. I personally think he was scratching himself there as an effect of the starvation. But, an insect bite in that area is also of interest.
Also, remember the CCSO is releasing this stuff to generate interest in the case. They want him identified.
The photos are beneficial for the community looking into this poor guy. After all, I think in addition to wondering WHO he is, we all wonder WHY. The photos help resolve that. But ultimately I do agree the photos are somewhat intrusive.