This is a continuation from the last topic: route aggregation.
When you advertise an aggregate, you effectively ‘hide’ topological information and can cause suboptimal routing. If you have 10.1.0.0/16 and 10.2.0.0/16 summarized into 10.0.0.0/8 and advertised via two links, one of the links may be the ‘best’ path for the traffic to take, but since the rest of your network has no knowledge of the real ‘best’ path, it may take a suboptimal route.
security without obscurity 