Currently, bespoke network and security infrastructure needs to be in place to support on-premise, or private network, runners from Bitbucket pipelines, which adds additional burden to the engineering and security teams looking to migrate to Bitbucket pipelines. 

With Application Tunneling to Bitbucket Runners, or an Orchestration Proxy, to manage On-Prem Bitbucket Runners, the burden is significantly reduced, and allows for accelerated adoption.