Google likely uses clickthrough rate (CTR) in their algo. If your site has a high CTR, it should hypothetically rank higher, so it makes sense for them to inclu

Google likely uses clickthrough rate (CTR) in their algo. If your site has a high CTR, it should hypothetically rank higher, so it makes sense for them to include it in their algorithm - to the point that it can't be manipulated. So, if the metadata doesn't directly increase rankings (which I'm pretty positive it won't), it can indirectly do so by grabbing the users eye and improving CTR, which I am most certain it will.