The Gerrit trigger plugin triggers a build for each event. This is with the assumption that the build will run only for that specific event. This works well for short duration pipelines. 

There are scenarios where the pipeline might run for a longer time, and in such cases, if we trigger one build per event, and number of events is high, then the total time taken for all event to get validated will be high. The number of builds in queue will also be high. 

In such scenarios, gerrit trigger can be used just to trigger the pipeline but pick the latest commit available at the time of checkout. So if the pipeline is running for 1 hour, then the next build will validate all the ref changes that got merged in that one hour rather than just validating one ref change. 

so in order to use gerrit plugin only as a point of pipeline trigger, we need a new feature which will not trigger many builds into queue.