Reinhardt doesn't really need to get to the high ground of the attacking spawn on King's Row for any reason, but that didn't stop one player from making it happen.
The clip, posted to Reddit by user DPS__Mercy, starts out in spawn with the player on Wrecking Ball and grappling on a chandelier.
As they swing towards the high ground, right before they leave the hero change area, the player quickly switches to Reinhardt and just like that, the crusader has the high ground.
Why Reinhardt would ever need to get up that high, other than to mess with unsuspecting teammates, is unknown. There's a chance a charge could connect from there, but it would have to be calculated perfectly.
DPS__Mercy gives an example of Reinhardt's charge from the high ground, and he's able to reach the first checkpoint no problem, but this could be an unwise move though if the player gets caught all by themselves.
Overwatch players are known for being able to find bugs and exploits in-game and sometimes even use them to their advantage.
Only time will tell if we see this strategy actually used during a match or if it's just a fun little exploit, but there's still a few months for pros to try it out before Overwatch League's second season starts in February 2019.