As of right now, distinguishing between "Away" and "Sporadic" isn't particularly useful. The use case where expected away time is important is when waiting on a code review. However, an "Away" status is automatically added to any user who is listed on a calendar event as of "right now" at any given time.
Status is useful to determine expected unavailable time, and simply reading the user's calendar availability should suffice for that. Unless other use cases come up.