"Control on" is triggered any time on is received, but not triggered on off/dim/bright/etc. If a device (motion sensor in this case) is already on, a control condition will still trigger a program evaluation even though no change in status occurred. An off command will not trigger a program execution. A control condition is true only during that point when the expected condition is received. "Control on" is false at all other times.
"Status on" is triggered by ANY change in status, and is true at all times when the status is on. If the device is currently on and it transmits another "on" command, a status condition will not trigger since it is not a change in status.
Use of control versus status is based upon the desired logical result.