The Overhead Cast.
When fishing with the Salmon fly rod, a good Spey caster will tell you that there are not many scenarios where you need to use the overhead cast, whereas if you are a trout and Grayling angler, the overhead cast becomes a welcome addition to your armoury especially if you are a dry fly angler, as the overhead cast is not only used to expel water from your fly prior to it alighting on the water surface, but it can also be a great asset when accuracy is paramount.
The overhead cast can also be used as part of a combination cast such as the roll cast pick up which can be used in several scenarios on both river and stillwater, or as a component of several slack line casts that are essential to combat many river situations relating to speed of flow and complicated currents.
Finally, the overhead cast is often neglected when learning how to double haul which is a major error, as the overhead cast is a pre-requisite to becoming an efficient double hauler, especially if your intentions are to achieve greater distances on reservoirs, become a successful salt water angler, or simply enable you to tighten up those loops when trying to cast into awkward places on the river, such as under overhanging trees etc. (see Single & Double haul).