Here's a pattern you'll recognize: a decision gets made, three weeks pass, someone new joins or someone forgets, and the team spends another hour re-arguing it. Multiply that across a program and you lose days a month to settled questions.
A decision log fixes it for almost nothing. One row per decision: the date, the call, who made it, and the one or two reasons that mattered. That's it. No prose, no minutes.
The value isn't the record. It's what the record prevents. When someone reopens a decision, the answer is a link, not a meeting. And when the context genuinely changes, you can see exactly what you assumed at the time and decide on purpose to revisit it.
It also protects the team in an audit or a postmortem. "Why did we do it this way" has a dated, attributed answer instead of a shrug. In a compliance program that difference is the whole game.
Most teams skip it because it feels like overhead in the moment. It isn't. It's the cheapest insurance a program can buy.