They cared about it before the stadium scheme occurred. It's nonsense to suggest this was just a nothing honour. Why would cities around the world seek to retain theirs?
Well I will not pretend to be an expert on UNESCO WHS sites and the benefits therein to a city or a site, (Stonehenge isnt a city, pretty sure its a WHS though)
My amateur understanding is they are in place to protect said sites from being demolished/built on, etc etc. Not a clue if they get cash from UNESCO in return. Preservation if you like.
So, it comes back to the old record; what, exactly does Liverpool gain from a wasteland having WHS status? If its billions in tourism/cash, then sound.
And the flip side is, what, exactly does Liverpool gain from the redevelopment of said wasteland? If its more, in ££££, I think LCC would be in dereliction of their duty to the city to hang onto their certificate