>Why would a search engine (1997) make glasses (2013)?

It literally was just because Sergey Brin thought it was cool.

I was contacted by their recruiters recently and started getting warmed up on their interviewing, etc. However, this was back in December when they put out ads against Apple's choice to allow users to opt out of tracking. It kind of made it difficult to want to follow through on the interview process after that... so I didn't.

Yes, LeCun is still head of AI research there, and he's a big draw for talent. Any advancements like this (unsupervised learning) are a huge boon for technology. Often, the most time consuming part of machine learning is creating the labeled dataset. It's amazing to see what can be achieved without one.