IMHO, your premise is off. Your Wiim may not change the data, but sending data is more than changing data. It passes the musical signal...data, sent with timing and with or without various types of noise in varying amounts.
There are hundreds of threads and articles about the differences in sound quality comparing various streamers. In a system with a worthwhile DAC like the Yggy, you should certainly have differences in the sound quality of a streamer. While the Wiim Pro certainly punches above it's cost, chances are good that you'd hear improvements in sound quality with a better streamer.
The quality of the power supply is a significant component of the performance and MANY use external linear power supplies from companies that specialize in these. In fact, many Wiim owners use those too to the best from their Wiim streamers. Personally, I prefer a separate LPS, as much of the best gear I've heard, especially preamps and streamers, keep the power supply external. With digital, a big piece of the puzzle is fighting noise via various strategies. Better streamers with good power supplies are a key example. Cheers,
Spencer