There are some people who will misunderstand or forget the topic of the conversation and pack their sentences with tangenial, unncessary information.
The other person in the conversation must interrupt or ignore that, or there's risk that the time spent talking will be wasted on the tangent.
Sometimes what appears to be a tangent is actually an introduction to a previously unseen but crucial aspect, but that needs up front connection in order to hold the listener's attention.
Of course, this all only matters when the conversation has a specific goal.
The other person in the conversation must interrupt or ignore that, or there's risk that the time spent talking will be wasted on the tangent.
Sometimes what appears to be a tangent is actually an introduction to a previously unseen but crucial aspect, but that needs up front connection in order to hold the listener's attention.
Of course, this all only matters when the conversation has a specific goal.