Ce vs. eC

In practical terms, what are the advantages of configuring a radio as e.g., 5825 eC instead of 5805 Ce?

I understand that radios set as one won’t talk with radios set as the other, because the control channel is different, but other than that, is there any practical difference in frequency usage, interference advantages, or whatever?

Or is it just that if the 40Mhz channels “fail down,” they will fail down to different 20Mhz channels, one of which may be preferable to the other due to ambient interference in the spectrum?

It’s just about selection of the less crowded frequencies.