Gary ... I luv ya man, but IMHO that is one RIDICULOUS statement, and I am happy it wasn't YOU who said it ...
While I agree that it depends on the venue and the audience, I also have to ask if some of us only play for dancing crowds? ... And if we are playing for NH are all of our audiences DANCING??? About a month ago, as part of the program I prepared for a NH gig, I played "Lady of Spain" using one of the accordion voices on the Pa900 and the audience responded to it even better than I thought they would ...
And as Donny said, there ARE times in a cocktail or background music setting - like what was shown in John Legend's video - when a song like this is going to 'capture' an audience ... granted it may not fit your "foot-stompin, dancin', hand-clappin' audiences" but that does not mean it isn't a beautiful song ...
And do any of us here not learn songs just for our OWN enjoyment???... there are any number of songs that I play at home that might not play on a gig ...
I might not be able to perform this song well enough to play on ANY gig, but that doesn't mean I won't try to learn it, even if only for myself ... just sayin' ...

And I believe the term 'cover' applies to someone performing a song that was made 'famous' by someone else ... in other words, every song we play - unless it is our own original material - is a 'cover' ...