There's small things that can make it questionable.
Like, on the stats page mastery is still described as the 7.2 mastery despite the page apparently having been "reviewed and deemed updated for 7.2.5". And the numbers for all of the shardbit generation are taken directly from the patch notes instead of the game, so they're all wrong. It's not particularly useful if you're just learning when the core mechanic is spelled out incorrectly.