Man, you forgot about the ability to save home menu arrangements, feature introduced in 9.6. This is totally a game changer.There is no need to use a workaround to access the internet/eshop and you no longer need cryptofixed CIA's.
For those who didn't get it, this is sarcasm. I'm sure no one cares about home menu arrangements. And since it's the only feature that got introduced since 9.3 (apart from the extra stable New 3DS, and I'm not only talking about the extra stable 3D!), then the reasons to update are only what @KobraXMW said (and it's especially stupid to have to use a cryptofixed cia to play a game that requires 9.9 and that you own in cartridge format).
