The Bitbucket Branch Source plugin works very well and is perfectly integrated with Jenkins.
- job triggering by webhook
- automatic creation of webhook
- build of branches
- build of PRs (with/without automatic local merging on target branch)
- notification of build status back to the Bitbucket server
- entire project organization
I don't see the point in developing a new plugin which will take time to reach functional parity (missing build of PR is a deal-breaker for many of us) whereas Atlassian could have contributed to the existing one and even become the official maintainers since the Bitbucket Branch Source plugin is up for adoption.
Mikaël Geljić: The Bitbucket Branch Source plugin is perfectly functional (even for PR build) with recent Bitbucket server releases but you need to tick the "Call Changes api" option for your Bitbucket endpoint in Jenkins global configuration.
Niket Joshi: The Bitbucket Branch Source plugin sends the notification of build status to the Bitbucket server and it doesn't need to be combined with multiple other plugins (except the Git plugin) to get a working pipeline.