Eurocopter's Hybrid Helicopter-plane in flight

Eurocopter's hybrid copter X3 has two turbo props mounted on short span wings, in addition to the usual rotor system (five bladed), which enables cruise speeds 50% higher than helicopters per se.
It is on a month long demo tour of the USA. Its first flight in Texas:

What special functions do those turbo props on the wings serve ?

Generally the rotor on top is tilted to provide the thrust required for horizontal flight. The absence of wings in regular helicopters also means that there is no lift as in regular planes. This hybrid provides some lift and thrust so that the rotor is used optimally. Overall power efficiency and handling is expected to be better as well as a higher speed in level flight.