Talk:Sona/@comment-10813891-20160403022828/@comment-6726953-20160403024410

It shows the unit as an entirely red object in its idle state; if it's moving, it shows the unit in multiple places over time again in an idle state, revealing the path the unit is moving in, so instead of giving true sight it basically allows you to predict their location so it's easier to dodge/reposition yourself against their next attack or to judge where to fire a Skillshot at them.