The direct cost is overpaying for weaker capability. The indirect cost is harder to see: bad routing decisions, misleading evaluations, latency regressions, and support incidents caused by behavior you did not expect.
Mismatch risk is especially important when you ship agent workflows, tool-calling systems, or customer-facing assistants that depend on predictable reasoning and instruction-following patterns.
Verification does not remove risk entirely, but it gives you a measurable signal before you scale traffic or sign a vendor into a production path.