When Cheaper Models Cost More: The Hidden Expense of Reasoning AI

The comparison between Claude Haiku and Gemini 2.5 Flash exposes a critical flaw in AI cost optimization: per-token pricing masks true expenses. While Flash offers lower token rates, its extensive reasoning overhead consumes far more tokens, resulting in 8.6× higher costs per request. This highlights why AI infrastructure demands the same rigorous cost instrumentation and failover strategies as traditional financial systems.