A VPN and a private interconnect can both get traffic from point A to point B. What changes is everything about how that traffic gets there — and most teams don't realize how much that difference costs them until they've outgrown a VPN-based setup.
A VPN is a tunnel over someone else's network
A site-to-site VPN encrypts traffic and routes it over the public internet. That makes it fast to stand up and cheap to start with — but it also means your latency, jitter, and reliability are at the mercy of whatever path the internet happens to choose that day.
An interconnect is a physical, dedicated path
A private interconnect is a dedicated circuit between your network and the cloud provider's network, bypassing the public internet entirely. The tradeoff is upfront provisioning time and cost — but in exchange, latency becomes predictable, bandwidth becomes contracted rather than best-effort, and the traffic never crosses a network you don't control.
Egress costs tell a different story on each side
Cloud providers typically charge less for data leaving over a dedicated interconnect than over standard internet egress. For workloads moving meaningful volumes of data between environments — backups, replication, analytics pipelines — that difference compounds into a real line item on the monthly bill.
The right answer is usually both
Interconnects make sense for your highest-volume, most latency-sensitive paths. VPNs still have a place for lower-traffic or temporary connections where provisioning a dedicated circuit isn't worth the lead time. The mistake is using a VPN for everything by default, simply because it's what got set up first.