I'm in the opposite camp. Waymo has neat tech, yes, but already valuing it on par with Uber is absurd considering the sheer scale at which Uber operates. 70 countries, 15K cities, 36 million daily trips. And this isn't counting Uber Eats and other side businesses. Waymo will have to accelerate its operations to the max for the next decade just to catch up. And that's assuming operating at such a scale is even possible considering they have to provide and maintain their own (very expensive) fleet. And this isn't a brand new market - Uber + local taxi companies have already set a hard cap on prices that Waymo cannot cross.
There is no doubt they have a lot of catching up to do, but you have to consider their advantages.
If Uber goes away, Lyft or others can take over the entire market overnight, precisely because they don't have their own fleet or unique technology. Waymo is placing itself as first mover into a completely new category of transportation which will require capital investment and new tech, so it will be much harder to displace once it gets going. It could target automated cargo transport in the future too.
No doubt there are significant challenges along the way, but waymo has a real product powered by tech that actually works which could massively change a huge industry. They're also notably more mature than competitors, and have track record of successfully rolling out in a safe way.