Not completely worthless... its like having a dummy oil pressure light that only lights up if to high it low vs having an actual swept gauge. Just depends on the level of information you want. Since a wide band is not all that much more than a narrow band it would be pointless to buy a narrow band, but not if it was give to you or was dirt cheap.
2001 ZX3 2.0L Zetec-
Hatch Nation #42
Going through Rebuild See "The TICK Build Thread" for details (http://www.focusfanatics.com/forum/showthread.php?t=289168&referrerid=62897)