Opinions about a static mockup are cheap and usually wrong. Put the same idea in someone’s hands as a working flow and the real problems surface in minutes: the step nobody understands, the field nobody can find, the assumption that only made sense to the person who wrote it.
We build prototypes at whatever fidelity answers the question. Sometimes that is a grey-box flow made in a day to settle a navigation argument. Sometimes it is a polished, data-backed simulation used to win internal budget or test with real customers. The point is deciding what you are testing before deciding how much to build.
Prototypes are deliberately disposable. Their value is the decisions they let you make early, and treating them as a head start on production code is usually how a prototype quietly becomes a codebase nobody wanted.
