What is the purpose of the backlog of deploys? For example, let's say 50 commits all land on master within the same second. Why break those into many deploymen

What is the purpose of the backlog of deploys? For example, let's say 50 commits all land on master within the same second. Why break those into many deployments stretched across hours instead of deploying them all in the next event? If you landed a bad commit in the middle of that 50, it seems like it might not be immediately obvious once it was deployed that it was bad - and then 5 or 30 minutes later another commit is deployed on top of it. You might not notice a problem until hours after all of the commits have been deployed, which leaves you in the same situation as if you had deployed all 50 changes in one event, but in this model those 50 commits have been stretched over a much longer period of time between commit and liveness to users.