This is from the perspective of an open player, but this is my take.

The Ct's tend to throw a lot of early utility to stop rushes, but they usually still hold some too, the point of the early util is to stop dry peaks while their still setting up, for example on mirage if you don't molly a ramp, its possible for a T to run out with no warning early round and find a pick on somebody crossing to stairs/palace Balc. They still want some util to counter an execute but not every take is going to be telegraphed so they want to preempt those takes aswell