it's just a semantic matching algorithm with a really big computer to power it
And it achieved a milestone of human-scale lookup and response that we'd never seen before. It's still an impressive feat, even as a powered-up refinement of existing techniques and just another step on the road.
As for the brain, while the complexity gets huger the deeper we look, there's an excellent chance we simply don't need to build that level of detail ourselves to get useful results. We already have useful AI with much less, and it's getting more impressive every day.
I'm guessing we'll have non-sentient AI that can do human-level tasks and interaction long before we emulate the whole brain completely, just like we have useful and cheap flight without needing to build a whole bird.