I have the same FM transmitter that the author mentions. If you're worried about an extra digital-to-analog step somewhere in your audio pipeline: it's a moot point. The transmitter's acoustics leave _a lot_ to be desired: there's background hum, bass goes very flat, there's tons of intermodulation around center frequency, and center frequency itself tends to jump around when amplitude increases. For small Part 15 transmitters, this sort of thing seems like the norm.

Why not just solder on an FM transmitter to an existing USB Sound card? Seems like a 5-minute hack.