It's also easier and cheaper. The advantage of the Raspi method is, well, you get a raspi out of the deal which is usable for many other things other than just the dsi cid. Biggest Loser isn't that sexy of a homebrew loader with it's 8KB of memory.The Biggest Loser, as an exploit game, is used exclusively for recovering your DSi's CID. The CID, or Chip Identification number, is used as part of your NAND's encryption, and is one of two parts of the encryption key. You can also recover the CID with a Raspberry Pi when you install your NAND reader. There's a few ways to get it, using "The Biggest Loser" is just one of them.
And Feroz, the prices I mentioned were just a reference, but Loser should be cheap in your neck of the woods as well.