I don't know why not. It only makes it that much easier to get to your favorite DS games.
...or you just use sysNAND for that.
What exactly is the problem with running GBA and DS games with CFW? It isn't like anything changes... Unless maybe when you use firmlaunch they aren't reloaded into NAND? I'd really like to know it's had me wondering for awhile now
The FIRM used for GBA and DS games isn't the same as the one used regularly. When you launch a title that requires either of these, your console reboots into it. The problem with emuNAND is that due to the NAND redirection not being applied to either of these it will look for the title that doesn't exist in sysNAND (which is why you need GBA games on both nands for them to launch from emuNAND). The reboot patches right now always reboot to the NATIVE_FIRM, that's why loading GBA/DS games with those patches enabled doesn't work. What should be done is load the right FIRM whenever it's needed from the reboot patches (rxTools does this). I don't exactly know what the deal is with DS cardridges, though.