The 8GB is available here, but it's not stated until you look at specs.
And it's $70 cheaper.

https://www.pricerunner.dk/cl/37/Grafikkort?attr_60535069=100019509&sort=popularity

The XFX is only 8GB.

Sales tax in USA differs by state, which is why they aren't included in price listings, it would simply be impractical.
The reason they are cheaper here is probably the Trump import tariffs.