My main use case for VNS3 is secure multi-cloud and hybrid connectivity, using VNS3 as an overlay VPN controller. I use it for IPsec site-to-site tunnels, encrypted mesh between cloud VPCs, and centralized firewall control without modifying native cloud networking.
For example, I have deployed VNS3 in AWS to build encrypted IPsec tunnels between multiple customer VPCs and on-premises data centers. Instead of going through complex native peering plus firewall changes, VNS3 provided an overall mesh plus policy-based routing, reducing deployment time by fifty percent and simplifying MSP multi-tenant isolation.