Actually, there's two other places I can think of where there would be an advantage from their tilt.
The first is out of Atlanta to Birmingham and Chattanooga. As Bill Haithcoat, George Harris and I think Xyzzy will tell you, those routes are as curvy as all else. Of course, there are so many other issues with regional services to those two cities that simply having two tilting trainsets doesn't solve.
The second I might could see is the Pennsylvanian. I'm not as familiar with this route...and as I was typing this I was suddenly reminded about the high platform issue, the Talgos are low (actually medium?) platform cars and a recent post on another forum indicated that Talgo didn't have interest in high level platform vehicles so never mind.