Why A directed net has a net control station (NCS) that manages who transmits and when, so traffic flows in an orderly way and nothing gets doubled or lost. Participants check in, then wait to be called before transmitting. The one standing exception is a genuine emergency, which you may break in with at any time.
Watch out Giving your name and address from the FCC database is not required for a check-in (your call sign, and often location or status, is enough), and logging the time of every transmission is the net control station's or a net logger's job, not a rule for participants.
In a directed net, NCS runs the show: speak when spoken to, unless lives are on the line.