It's the most prestigious domestic Cup in the world. It has a history and prestige that no other domestic cup has.
Most football fans grew up with the FA Cup Final being a highlight of the season, many know who won the Cup in such and such a year.
I don't think we'd have had a parade for the Carling Cup. If we had I don't think many would have turned up.
It's clearly 3rd priority for the big clubs these days and clearly the CL has devalued it somewhat, but it's still a major trophy.