Some CICD services such as GitLab already provide docker image registries per project for free, and enable users to create any number of projects.

Similarly GCP registry if you are on GCP.

I have used them. It isn't that much of a hardship if you are already cloud native.

Companies with legacy or hybrid infrastructure may need to jump through additional hoops.

Similarly there is Azure Container Registry. Only issue I've found with it is that access permissions are not granular enough - for example, you can't specify that a user/service principal should only be able to access particular tags or repos. Not sure how that compares to the AWS and GCP offerings?