Gameboy Advance uses catridge. The memory card thingy you mention is not worth it for kids. As it requires certain knowledge.
Besides, the games for Advance is not expensive. You can get it at around 50 ringgit.
One pokemon game can last a kid of weeks.

I would suggest you get a GBA SP for the kid and a pokemon game with it.

DSlite is not worth it as it is more expensive and the games are expensive too. Not to mention there is no Pokemon game specifically for DSL yet. English poke game that is.

Worth it or not, we have one issue in hand. Adults are having difficulty taking care of a DS. What do you think will happen to a ds given to a kid?

My first machine was GBC, then i got myself a GBA after selling off my GBC. I trade in the first GBA i got for a better looking GBA.
When GB SP came out i wanted to buy but didnt. Then i discover the wonderful world of RO. From there i stopped console... 4 years down the line and here i am playing a NDS after so long playing online gaming.

Yes and no. No coz the graphic is not nice. Yes coz there is such game available.