Why is this brilliant?

This is a blitz game I played a moment ago. For some reason the move 17. Bd2 is brilliant. Anyone know why, or is this just engine weirdness?

(Please excuse the bad gameplay)

Because it sets up a discovery on blacks bishop. After black takes the knight on h8 you could have played Ne4+ to win that bishop. Although, you are already completely winning and it doesn't really matter. In other words, yes the game review system is a complete gimmick and I would mostly focus on the mistakes, inaccuracies and blunders. The great or brilliant are just the same as best moves with other useless criteria.

It seems like the move does satisfy some of the known requirements of Brilliant move classification, but probably need to mix little "weirdness" in there as you allude to. 

Let's look at the broad definition of Brilliant move classification: "Brilliant Moves must now sacrifice material in some way and must be the best, or nearly the best, move in a position."

So, looking at your position, we can see that Bd2 "sacrifices" the h8 knight is some vague sense, but surely the Game Review algorithm realizes the knight is trapped, right?  So that is why we need to mix in some level of "weirdness".  And apart from that, Bd2 is one of the top moves... although most every move is still winning in this position.

Keep in mind the following caveat which also might encourage the Game Review to mark this move as Brilliant: "Moves will also be a bit more generously awarded for newer players, recognizing that some strong sacrifices that may be standard for experienced players are quite an achievement for newer players."  You have played a lot of games on the site, but I still don't know if rating plays a role in how often "Brilliant moves" are handed out.

Cool, thanks for the info everyone.

The weird thing about this that Bd2 is not a sacrifice.

Honestly, only a chess.com programmer could answer the question. They designed the script that awards these ridiculous "brilliant" titles to moves. Other people can only guess.

One thing is certain, though: this "brilliant" label means nothing at all. It gets too much credit by beginners, who think that it is a real chess thing, but instead it is just a scam by chess.com.