A useful callout gives warning without flooding the group with low-value noise, so relevance and timing matter. If a warning comes too late, it is useless. If it is too vague or repeated constantly, riders start tuning it out. The goal is to provide a technical requirement for the riders behind to react to, not just a general observation about the road surface.
Communication should be direct and specific to the hazard. Shouting a warning for a pothole that the lead rider has already cleared does little but create noise. The timing must align with when the following riders actually need to adjust their handling.
How do you balance the need for safety warnings with the need to avoid low-value noise during a fast group ride?