If the video or collection has not been delivered to anyone (via the Delivery feature) and only a Share Link was provided to viewers, deleting the video or collection will permanently remove it from our platform and prevent further viewing of it by anyone. So in this situation, yes, you must keep the content in your account for viewers to continue to have access.
However, videos or collections that have been delivered to one or more recipients (via the Delivery feature, learn more here) cannot be deleted. This prevents you from inadvertently deleting a project that you may need to make changes to in the future (such as privacy settings, etc.). In this situation we prevent you from deleting it, so you do not need to worry about accidentally deleting it.