playing eshop games & updates (will work as long as you get the games before 7.0 so you don't have to go to eShop after to get forced to update)I'll only be looking at Ace Attorney 5 if anything from eShop. What other benefits are there for updating to v6.3 EmuNAND? I realise that v7 might be coming soon
streetpass plaza etc(might not work after 7.0)
you can't play multiplayer online but some people can do local play so thats good if you like that
play retail carts requiring firmware upto 6.3 (this I don't understand why not just sell the games and play rom? Only pokemon and animal crossing don't work and the gwteam are adding support for that before xmas hopefully)
The reason why everyone is updating to 6.3 is the fear of being blocked in the future. You can run all games except the two stated fine with just changing launcher.dat