Art Critics. Worth their salt?

I really don't think I could be an artist. I could possibly gain some skills in applying paint to a canvas but that isn't what makes me want to stay on the other side of the creative spectrum.
What other job can you do where you work for years only for someone to judge your life and career in 3 seconds. The lives of many a creative are in perpetual turmoil resulting from ecstatic praise or crushing criticism. Sometimes fragile egos take a battering from the casual curt comment.
I have massive respect for these artists for who the vast majority, do it because they love it rather than for financial gain. To articulate their imagination as art is a process that fascinates me.
Thalia Allington-Wood has written a review of the opening of Mooch Art and Revolve Gallery in the triangle. Click Here. Generally positive but one of Revolve galleries artists received some criticism which is highlighted as all journos are adept at doing.
The question is whether art criticism can be constructive given the subjective nature. Can someone telling you they don't like Marmite be of any benefit to people who haven't tried it but love a tasty, nutritious, salty spread on their toast (My cheques in the post).
My feeling is that everyone's opinion is valid and the only way the gallery will get better is with feedback. I have mentioned in a previous blog that browsers who are positive about everything leave me a little lost. Smoke blowing or fence sitters are terrible for galleries especially if an artist isn't selling. Perhaps the worst criticism would be apathy, if people came to the gallery cocked their head to one side and sighed at how mundane it all was then I haven't done my job properly.
So art critics are needed just as all other customer feedback is needed. They are worth their salt but just take their comments with a pinch of it.

Just read a great article in the guardian by Jonathan Jones see below.
CLICK HERE