"Uber getting involved in autonomous cars makes absolutely zero business sense"
Er... if this is truly your thinking, you'd make a very poor CEO.
Self driving technology will make companies like Uber completely obsolete unless they either get on the badnwagon, or find a partner - and there aren't many left. Tesla is already working on building their own autonomous ridesharing fleet to compete with Uber. Ford has also purchased a ridesharing company. BMW is starting their own. Lyft is partnered with GM.
This is all a giant race, and we don't know who will come out on top, but if Uber just sat around and did not invest in this area, they would most assuredly be out of business in under 10 years.