The reason why it?s considered so serious is because sometimes these sickos pay people to abuse children and capture the images for their own viewing pleasure over and over again.
Imagine if all those 50,000 images were of different children
and it depends if it?s extreme material or not, some person get caught with image so and video of kids being burnt alive, the more extreme the higher the chances of simply viewing the material wouldn?t be enough and he?d find satisfication in harming children.