Gaming in general, sure, from an immersion perspective a wide soundstage is great. But specifically in the context of competive FPS, its really not that important, in fact I personally find an overly diffused soundstage can be detrimental at times.

It's worth remembering that pro players are more often than not running IEMs or even standard gaming headsets. Also, the guys you mentioned aren't competitive gamers, in fact, crinacle himself has made this exact point, not so much specifically regarding soundstage, but just generally that it really doesn't matter that much beyond having a neutral/bright leaning sound signature.

It's all preference at the end of the day, there's nothing wrong with the 800S, but if you're spending over a grand on a pair of headphones in the hope that they'll make you win games more often, you're gonna be disappointed... And poorer.