Crossfeed actually does mix the channels together but it doesn't do it indiscriminately. The level of crosstalk varies with the frequency and drops off as the frequency increases. This mimics the way sound reaches you ears IRL. Lower frequencies with longer wavelengths will bend more around the edges of obstacles, such as a person's face. This means that the lower the frequency the more you will hear it in both ears even if source is at an angle to you and one of your ears doesn't have a straight line path to the source. These difference in volume between each ear that vary with frequency and angle are one way that your brain determines what angle a sound is coming from.
prefer a wide soundstage over a deeper one then crossfeed isn't for you. If you are bothered by those you can use crossfeed and trade some soundstage width for it. Even binaural isn't perfect as individual HRTFs can vary quite a bit from the averages used to construct HATS. The fewer compromises you make the less music you'll have left to listen to.
You can talk about it's limitations or just not like the effect but it has a very firm basis in psychoacoustics.
Very nice writeup on psychoacoustics and stereo. The old audiophile myth of "stereo is best" gets somewhat tiring, even for speakers. Stereo was simply a crude approximation or real world listening as theorized by recording engineers in the mid 20th century. It's not the magic be-all and-all of audio that many make it out to be. For headphones there's binaural, for speakers there's real surround recordings. Both are sadly very limited in quantity.
But that's why I get irritated with all the excessive pushing for amps and headphones and tubes etc that add "more soundstage" since, IMO they're long-shot expensive attempts to correct what is in essence a flaw in the recording. What's on the disc isn't very much like real life. Sure one piece of gear or another may have elements of a bigger soundstage, but they're small fixes for the core problem of needing to move recording technology forward before playback technology means much of anything. It doesn't work for headphones but the genuine multi-channel SACDs/DVD-s, that weren't botched by the recording studio, give a taste of what we should be looking for!
We need new recording technology and recording methods for any real improvement in audio to take place. Virtually no one seems interested in investing in that technology, except Cheskey....thank goodness at least someone gets it!