[quad_eye_oh]

Seems like it's about symmetric costs and overall efficiency. To get up and walk over costs the Boss time and physical effort, so it won't take happen frequently, and it will likely happen on a predictable schedule (e.g. as boss goes to lunch). Context cues are available, and clarification is instant, which minimizes time-wasting rabbit holes.

In contrast, for the Boss to rattle some misguided text into Slack takes much less effort on the Boss's part and doesn't break the Boss's concentration, but the misunderstanding will be harder to clear up. If there is a back and forth it will take longer and be more distracting and stressful to the engineer, and if there isn't a back and forth the engineer is more likely wondering wtf the Boss is on about.