One application interface
Direct integrations with every provider repeat work on authentication, requests, and errors. A unified gateway gives applications one interface while handling provider differences centrally.
Reliability and governance
A gateway can apply authentication, rate limits, logging, and failover policies. Teams can attribute model usage to projects and keys to understand incidents and spending.
Keep model choice flexible
Developers can compare task quality, speed, context windows, and pricing without rewriting the application for every provider change.