In other words, in order for the offense to score, you need to complete passes until someone catches the disc in the end zone. The accepted method of doing this is to complete shorter, high-percentage passes. On a non-windy day, it seems fairly simple for at least one of your six teammates to get open and thus you can march down the field. Of course, one long pass, or "huck," can shortcut the process and give your team the quick score. Much like football, the huck is not typically done except in desperation (game almost over due to time or thrower almost stalled).
However, I am not at all sure this logic makes sense. Suppose you need six short passes to advance to a score. If your team completes short passes with a probability of 90%, you will score about 53% of the time (90% to the sixth power gives the chances of completing six passes in a row). In other words, as long as the chance of completing the huck is more than 53%, you would have a better chance of scoring with a huck.
Thus, the relative chances of scoring via the two methods depends on three things: 1) chance of completing a short pass, 2) chance of completing a huck, and 3) number of short passes needed for a score. The graph below shows the threshold huck completion rate (the rate at which it makes more sense to huck) for different short pass completion rates and always assuming 6 short passes is enough for a score and one huck is enough for a score.