If you have a old 3ds your gw wont be useless, but since you have the money to spare you can buy a Sky3ds for your n3ds needs since GW team already stated that they'll have some difficulties supporting emunand over 9.5 on n3ds.
More precisely, as they stated:
"We also want to inform our users about some news regarding emunand support for the New 3DS:
We will not be able to support emunand 9.5 or higher for a while on the New 3DS. This is only an issue for the New 3DS, the old 3DS and 2DS will never have this issue. This is not a definitive barrier, but we feel it necessary to inform our users that while we are still working on releasing our New 3ds support, we will not be able to provide support yet for 9.5 emunand or higher for New 3DS on release."