Humans can do a lot of things we don't understand how to convince software (...or other humans who don't intrinsically learn it very well) to do.

Lidar lets you get a high degree of accuracy for certain variables in your model - because you can know fairly accurately when and how strong the signal you sent out is, you can have a fairly high degree of confidence when you get reflection of how far away the object is, and feed that into your persistent idea of the world, versus having to use a bunch of heuristics to try and extract that from purely audiovisual data.

(That's my understanding, at least - I don't work in that industry.)