If your event requires programming, there's a few reasons why you want want to get in the habit to program into that track for the event.

1) Simply - Just so your programming isn't getting mixed up with your other tracks

2) You have non-members coming in for the event that won't have access to other tracks

3) If you're sending Announcements or Chalk Talk messages out, members/non-members will know if it's related to the event and non-members will be able to see the messages since they'll only have access to that event Track

If it's an in-house event, it may not be necessary to do that. Totally up to you.