I was thinking for expansion of software. Say you make a DS game that is like a game studio that lets you make games and trade them with friends. You would want to provide as many features for it to make it flexable, and cram the DS cart with sprite templates, sound effects, etc. You could then save the games out to GBA carts and take along the ones you want with you.
or maybe like some "Learn To Read" type software for kids, where the stories were all on seperate GBA carts that you could bring with you. Then you could store dictionaries and speach synthesis software on the DS so you could tap words, get their meanings and synonyms, and have the DS pronounce the word for you.
Just a few ideas I had for use with this type of thing
 I am a Gauntlet Adventurer.I strive to improve my living conditions by hoarding gold, food, and sometimes keys and potions. I love adventure, fighting, and particularly winning - especially when there's a prize at stake. I occasionally get lost inside buildings and can't find the exit. I need food badly. What Video Game Character Are You? |
Mega Man 9 Challenges: 74%
| Waltz | Tango | Jitterbug | Bust a move | Headbanging |
| Bunny Hop | Mr. Trigger Happy | Double Trouble | Mr. Perfect | Invincible |
| Almost Invincible | No Coffee Break | Air Shoes | Mega Diet | Encore |
| Peacekeeper | Conservationist | Farewell To Arms | Gamer's Day | Daily Dose |
| Whomp Wiley! | Truly Addicted! | Truly Hardcore! | Conqueror | Vanquisher |
| Destroyer | World Warrior | Trusty Sidearm | Pack Rat | Valued Customer |
| Shop A Holic | Last Man Standing | Survivor | Hard Rock | Heavy Metal |
| Speed Metal | Fantastic 9 | Fully Unloaded | Blue Bomber | Eco Fighter |
| Marathon Fight | Quick Draw G | Quick Draw C | Quick Draw S | Quick Draw H |
| Quick Draw J | Quick Draw P | Quick Draw T | Quick Draw M | Quick Draw X |
