They do have a sizeable real world impact. Moderately sized organizations usually build and store the images in a public cloud, which in turn do not provide any straightforward registry cleaning capabilities (at least I didn't find any in AWS or GCP). This leads to hundreds and thousands of gigabytes being wasted and money being flushed down the drain. Not to mention that network traffic in public clouds can quickly rack up the bill as well.
This Docker and Kubernetes hype and the fact that few people understand and care to implement these technologies correctly fills Amazon's and Google's pockets with money that could be spent elsewhere.