One task contains several kinds of work
Repository search, architectural planning, mechanical editing, and test repair do not place the same demands on a model. A router can reserve deeper reasoning for uncertain decisions while sending compact edits to a faster path.
The tradeoff is legibility
Automatic selection is convenient until a result is unexpectedly slow or shallow. Useful routing needs enough trace information to show what was selected and why, without requiring developers to become model schedulers.
Evaluate the finished change
Model choice is an input, not a quality guarantee. Teams still need focused tests, readable diffs, and review standards. A routed workflow succeeds when it reduces waiting and cost while preserving the evidence a reviewer needs to trust the change.