Nissan decided some years ago that they are likely to have a problem getting away from the ‘cheap wheels or hefty sports utility’ perceptions which had become mounted on their products in North America which is a market too big to disregard.
Additionally they wanted to stretch themselves, a lot as Toyota created Lexus as a premium brand, then so Nissan created Infiniti.
Sometimes the brand has been accustomed to springboard new ideas, like the FX, which can be considered too outrageous for the sensibilities of traditional Nissan buyers.
The cars are less radical in looks (the G35 Coupe may be the exception to rule) compared to products from the parent company, but you are to not be wiped off as ‘old fart’ machines; frequently there are some pleasant surprises (for example adaptable suspension, sweet engines, neat interior goodies) that are either unavailable or unaffordable in the Nissan range. They’re quite profitable towards the group, too.