You can choose to set the privacy of each deliverable to "Public" or "Private" in Deliverable Settings.
For public deliverables: Client can simply share their URL with anyone else. As it's an unlisted URL, only people with the link can view.
For private deliverables: Private deliverables have a built-in sharing option, and clients can easily send a private invite to their friends/family to access their video or album. Each shared recipient also receives a unique access code. Client always stays in control of the privacy, and can also revoke access.