Answer
High availability is built to reduce downtime by keeping a secondary path warm enough for faster failover. Disaster recovery is the broader discipline of restoring the business after a larger disruption, including site loss, access dependencies, communications, recovery order, and validation. HA can be one part of DR, but it does not replace the full recovery design.
Buyers should be careful not to treat replication alone as a disaster recovery plan. A real DR design proves where the business will run, who declares the event, and how teams confirm that critical work is actually back.