Many egg donor agencies and clinics write the Donor Sibling Registry right into their contracts/agreements so that recipient parents and donors have access to each other right from pregnancy/birth.
CONTACT: The issue of contact between the donor and the recipient is removed from the hands and focus of the agency/clinic.
CONSENT: Since the DSR relies on mutual consent contact; the agency/clinic doesn’t need to be worried about protecting anyone’s privacy or incur the costs of tracking communication between donors and parents.
CHOICE: Each party can remain private if they choose, so the decision is ultimately in the hands of those involved. Each party can decide the depth and breadth of the information they’re comfortable sharing. 
CURRENT: The sharing and updating of current medical information happens on the DSR, so the agency/clinic has less work since they have provided a tool for medical updates.
EMPOWER: Parents and donors are empowered to set the parameters of their own relationships, without a middleman, and without having to wait18 years. Donor-conceived people have the opportunity to establish relationships with their genetic mothers/fathers while they are developing, not having to wait until they are adults.