That's not a good question, since it applies not merely to surrealism but to all artistic expression whatsoever.
You might as well argue, what's the point of a painting of a beautiful woman when there are beautiful women out there? What's the point of a novel about someone's life when people have interesting/tragic/comic lives? What's the point of writing music when the sound of children laughing or the wind in the trees sounds perfectly nice as it is?
Life is one thing, art is a slightly different thing. People seem to make art, no matter the circumstances, so to suggest that it's 'redundant' is neither here nor there - it's still gonna get made. Art isn't there to move us the way that a photograph of an atrocity moves us; it's not what art is good at, although personally I think 'Guernica' is an exceptionally powerful picture. To confuse them the way you're doing is either to reduce all art to politics (like insisting that art should make us angry the same way a picture of a screaming Vietnamese girl makes us angry) or, what's worse, to aestheticise real life - 'Look, there's a melted watch, isn't it just like Dali? So therefore why do we need Dali?'
Dali was trying to do one thing when he painted a melted watch, the US Army Air Force was trying to do something a little different when it bombed Hiroshima. Remember that.