It might be useful if you have a divx encoded file that you want to play by plugging a device into your receiver (SD card or thumbdrive or whatever that receiver may support for an input/backup device).
I forget what format was supported by the Pansat 3500SD that I obtained for my friend (MP3?), but if you took a file of that format, put it on an SD card, and plugged it into that receiver's SD card slot, you could play that type of file through the receiver.