It depends how honest the people giving the scores are being. If the score is truly an honest summation of the pros and cons of a piece of artwork, then I'd say it's a valuable indicator of how good a piece of art is on the technical level. I think some of the scores on my art (some below 4) are very fair. And I pay particular attention to those in terms of spotting flaws. Those scores are an aggregate of hundreds of opinions so it's a fair sampling of data, if nothing else. But it is a flawed system as there is no way to guarantee the honesty of voters or that they are voting based on valuable criteria.
Anything with below 60 votes, I generally ignore the score (high or low) because the sampling is too small. When you're in the 60 minus zone, especially if you score well on your art, it only takes one zero vote to drop the score drastically and significantly more 5 votes to bring it back up the same amount. Usually, I'll accrue a bunch of 5 votes for one voting period which will slowly hike up the score, then have that increase nullified by a single 0 vote once the next voting period starts. And this happens pretty much ad nauseam until over 60 votes.