Gaming Un-sparse data?

[Kayot]

I was toying around with my NTFS filesystem and I read about how sparsing Wii iso files would free up a ton of space.

So I did the following command:

D:\Temp\fsutil sparse setflag "New Super Mario Bros. Wii.iso"

At first nothing happened, so I assumed it failed. I figured, not one to let this get me down I decided to compress the file through NTFS compression. That's when I noticed that every file in all the sub dirs was smaller on disk. I'm guessing the sparse went through on all the sub folders.

So, is there a way to turn it off and what are the implications to leaving it on?

I googled like crazy and most of it was doom and gloom, with a hint of cool added. I'm wondering if I should undo it and just stick with ciso files.