The Reddit user who posted it goes by ATwerkinYoshi, which is a giveaway for the player's silliness and ingenuity.
It looks like he really got the boxing glove rigged up effectively, as it is appears able to easily distinguish between the player using Seismic Slam, Rising Uppercut, and Rocket Punch.
I'm not convinced it's a better way to play than a mouse and keyboard, or even a controller, but if you want to get toned while still playing Overwatch, maybe creating a DIY motion controller isn't such a bad idea.
It reminds me of a certain Nintendo peripheral from decades ago, and it looks like I'm not the only one.
ATwerkinYoshi touts on his Twitter page that he can, "beat any game with any controller." He attempted Legend of Zelda: Ocarina of Time with Rock Band drums, among others.
ATwerkinYoshi outlined the process of creating the boxing glove peripheral in a lengthy Imgur post.
"After streaming for two hours, my arms are dead," he said. Rest up, we're all hoping to see him stream more gameplay of his homemade Doomfist gauntlet in the near future!
Photo courtesy of ATwerkinYoshi