If you were hoping to import Japanese games for your US Nintendo 3DS, this is bad news. If you want to play imports, you will have to buy a foreign system since a 3DS from one territory will not play games from another. It won’t even show up in the menu.
This is confirmed for the Japanese version so it is safe to assume that the US version will work the same. To some this is not a deal-breaker, but to others this is a big issue. If you want to play foreign games, you’ll need a 3DS from the same country.