You want it if you want to play your own converted PS1 games with sound. Sound for PS1 games is handled by the Vita itself. It's not emulated within the PSP emulator like everything else is. When using TN-V, you're locked into the PSP emulator, so you won't have sound with custom made PS1 Eboots because it can't normally access the areas of the Vita that emulator PS1 sound. Total Noob made a plug-in that would let PS1 games have sound, but it was really buggy and didn't work for every game. This new exploit will let custom PS1 games run perfectly, with sound. None of this is an issue though if you don't want to convert your own PS1 games. If you just want to buy games you've bought from the PSN, then don't worry about it.