Programs lose time when a pattern is treated as obvious. The original constraint is gone. The people who accepted the residual risk have moved. What remains is a diagram and an argument.
An architecture decision record is not bureaucracy. It is the cheapest way to keep the choice, the alternatives, the consequences, and the owner in the same place. Without that, every incident becomes a redesign.
Keep the rationale with the decision. Otherwise the decision will not survive the people who made it.