One of the big missing features in Bitbucket cloud is package registries. I say "missing" because it's about closing the loop.

For example, a Java app whose code is in Bitbucket repositiry A depends on a library whose code is in Bitbucket repository B. A and B are both built by Bitbucket Pipelines.

In the above scenario, we shouldn't have to add another system (e.g. Artifactory) just to make two things that are both in Bitbucket be able to have a dependency relationship between them.

GitLab and GitHub both have package registries, with various degrees of maturity and polish. They have both recognised the importance of closing the loop with respect to dependencies between repositories within the same organisation.