Quadra-SPF+ and Quadra-SPF28 are connections that bundle together 4xSPF* connection at once. However you can split the lane and having 4 real ports by using a breakout cable. One plus of this kind of connection is that you can use 1 port to connect 4 different devices. This is extremely usefull in order to create a High Available Networks.
Instead of connect to 1 switch you can connect to 2 different switch by using 1port.
Port splitting can be really helpfull.