Even for someone who seems to be living on top of the world and is succeeding in ways we can't even imagine, one of the most important things is that regardless of who you are, what you've accomplished or what you're doing you have to be comfortable with yourself and who you are on all levels. Gus' sexuality doesn't make him into a better skier, but hiding it and dealing with the pressures of a being well known in a heteronormative sport can and has changed the way he competes.
In the ESPN article Gus talks about going from a silver medal at the Sochi 2014 Winter Games to failing to make the podium at the Winter X Games. It's very difficult to be able to stay focused on your event and succeed when you're afraid of losing it all over something you have no control over. That's why it matters and it's important that Gus came out, even if it's a non-issue for the rest of us, for Gus it's finally coming to terms with himself and removing the barriers that are holding him back from reaching his true potential.
I had the distinct and (random) chance to meet Gus before he flew out to Los Angeles in September. He noticed I was wearing a shirt with the Olympic rings and asked me about it, not at all mentioning who he was (or the fact he was an Olympian himself) until I asked him what his sport was and didn't even realize who he was until much later. Fortunately I ran into him again and got the opportunity for a photo, while I think he is handsome and cute, his sexuality never crossed my mine. My impression of him is that he is humble, friendly and just wanting to be himself and succeed in his own way like the rest of us.
If you haven't yet, give the article a read. I've read several autobiographies of LGBT Olympians and his story is equally as impactful. Being able to make a difference in the lives of others is the most important thing one can do, even better if you can be yourself when you do it!