For me it's mainly because I'm a huge Braves fans. I still remember his opening day first at bat home run during his rookie season.
Jason Heyward has had a very serviceable MLB career. But it's mainly due to the hype that was built up for him during his rookie season.
The hype for him during his rookie season was starting to get Paul Bunyan status, I still remember there were reports going around during spring training saying that the Braves might need to put nets in the parking lot (he had hit one home run that had left the stadium and busted the manager's car window) a lot of people thought that he was going to be the second coming of Barry Bonds, as said before he's had a serviceable career won a world series, was a part of one of the most historic world series ever, walked away with tons of money during his career mainly because of his defense.