How important is the plastic case in sales of DS games?

Remember way back in the day, when all GBA games right through to the end were in cardboard boxes?  How much did they suck (rhetorical).  I hated them as you ended up destroying them or flattening and storing them.  You never used them to keep the games in.  They just sucked.  I ended up putting all my GBA games, into DVD cases, 2 per case.  Until I did that, I just had them laying about in containers.

If I could get cheap, spare DS cases, I would put all my GBA games in them.

Now, GBA games did sell very well, but DS has eclipsed them many times over.  How much has the plastic case to do with this?

Even in the shop, it was hard to get a game that didn't have a damaged box.

I think that the plastic is some small way has aided sales.  They keep better and they display much better in the store.  Of course, we can't really quantify how much it has helped, but do you agree that the plastic case became a sales plus in itself?

I personally don't think it would really have had a major effect slaes wise. 

I keep all my GBA games in a small drawer, and all my DS games with my DS case.