What is the Advantage of wide chord fan blade of aircraft?

A narrow chord blade weighs less because of the less massive cross section but their vibration frequency is too low to operate successfully without the use of a mid span shroud to provide added stiffness. Elimination of the mid span shroud increases the fan performance/efficiency.

RR was one of the first to design a successful wide chord blade and got around the weight penalty by developing a partially hollow titanium blade design. P&W followed suit. GE chose to solve the weight penalty by developing epoxy/graphite fan blades.