Isn't Black Friday just a gimmick to boost sales?

I have never shopped on Black Friday for Christmas gifts. I hate the crowds and anyway, aren’t the low prices being advertised, just a gimmick to get you in their front door? Most of the ads on television are showing sales items that appear to be made in China? One store adveritises diamonds at 50% off. one in particular had a sale price of $5,000 dollars. It’s now $2,500 dollars. Is the markup this much on diamonds? If so, that’s unbelievable. This is just one example. Question: Is getting up at 4 am really worth all the hassle for Black Friday? Is Overstock.com not a much better choice?