Publishing a protocol in the protocol library marks out that protocol as usable by other members of your team in experiments. The protocol templates created within your protocol library are all version controlled. So, when you create a newly published protocol template, it is marked as the published “V1” (version 1) which you can refine further by creating a V2 draft.
Each new version you create allows your team to reference the history of your protocol(s) as they have changed over time. Nothing beyond that is affected by publishing your protocol. Even if you do not publish the protocol, you can still use a protocol as a template when creating experiments. However you won’t benefit from the clarity that comes with marking the protocol as published and the power of version controlling.