It's much faster, so if you're not doing something cutting-edge, or you're doing the planning yourself and just using the LLM for implementation, the speed benefit outweighs the extra smarts of Fable/Opus5/Sol.
> Save your context. Always use a subagent (Opus 5 or GPT 5.6) for performing the implementation and then review the work yourself. You are the orchestrator and coordinator it’s up to you to ensure a cohesive final result.
I’ve done more or less the same thing with other agents/versions but with Fable consuming usage credits/tokens so quickly I do it more regularly than usual. I know people who will specify Composer (to my chagrin) as the implementing agent.
Addendum: this really goes a long way, and I can use a single chat session for days before I get into the context danger zone and need to compact/summarize.