It's why the question "do you play your own game?" gets asked. Because as much as people say yes they do, there are certain aspects that people don't touch when they play it. I'm no dev, but I don't play magical ranged much beyond getting it to cap and then forgetting it exists. Has to be the same way for anyone else who doesn't have a lot of free time to learn each and every intricate detail.

Of course, that's why you hire a team of playtesters and get them to play your changes. But why hire those people when you can shove them out the door for your playerbase to beta test for you? Works for Blizzard, and the toxicity you get from the playerbase is peanuts compared to what you save on hiring a dedicated team. At least by how anyone higher up would see it.