The Classic Controller is for some Wii but most suitable for Virtual Console games! Because it makes a lot more fun than having a GC controller (especially the Classic Controller's quasi wireless)
Conclusion: Those who like Virtual Console gambles should definitely set this controller. Otherwise not mandatory. The price is a bit high, but the workmanship is really good too. If you just looking for a classic and inexpensive controller and this must also be wired, should resort to a GC controller from BigBen or so - even so can play the VC-title.