Having your stuff in it already, it's always available immediately (for you), not needing to worry as much about getting it dirty at the beach or with a dog, going to remote places where calling a Waymo may be infeasible or would take a really long time. Probably also cheaper if you drive really frequently.

I don't know you or your situation, but many people (including the idealized version of Rivian's target market) like going places that Waymo currently doesn't. There's also tradeoffs with cost, wait time, # of passengers, cargo, etc. Some people may also want to automate "boring" driving while still having the option to do "fun" driving

My cars are more than just transportation. They're mobile storage lockers where I can keep my stuff reasonably secure. They're a place to sit warm and dry while I wait for something else. They're (semi) private changing rooms where I can put on my cycling kit. Regardless of who does the driving I'll never give up owning (or at least leasing) my own private cars.

If you want to leave the waymo boundaries?

Why do people own cars when they can just Uber?

I’m with you but there are plenty of places where public transit is superior to driving and people still drive.

Can you waimo to another city or to camping?

Because lugging around two child seats when you get out at the other end fucking sucks.