Creative SB X-Fi Sound Cards

I purchased a computer with such a card. The 4Front driver allows it to work for output only with Linux; but with FreeBSD, the 4Front driver supports only a few applications, even only for output.

On Nov. 6, Creative released a Linux source-code package for this device. It works fairly well, though it does not support all applications. Is there reason to expect that this will lead to a suitable driver for FreeBSD as well?
There is no reason to expect that. linux drivers can not just be compiled on FreeBSD, or even, necessarily, ported over easily.

Until some developer decides to try their hand at porting the drivers, your situation will not change.