A model that is not wired into a decision is a research project. Before building anything we establish what action the output will trigger, who takes it, and what accuracy that action actually requires, which is frequently lower than assumed, and occasionally far higher.
A great deal of what gets scoped as machine learning is better served by a well-designed query, a threshold, or a clearly presented dashboard. Those are cheaper to build, easier to explain, and do not degrade quietly as the world shifts. We reach for a model when the problem genuinely needs one.
When it does, we treat it as production software rather than a notebook: versioned data and models, evaluation against a held-out set, monitoring for drift, and a defined path for retraining. Otherwise the accuracy you measured at launch is the last honest number you get.