Dialog box when using Navigation for the first time:
Clicking "How to get started" in Maps help takes you here:
To me, this is pretty clear.
It didn't get pushed to any of my devices automatically. I reviewed the changes before manually updating Maps.
I won't debate the semantics of the word "clearly". Way too subjective a term. What's clear to you is clearly, to me, not clear to everyone

. And that's really all I'm getting at. There are most likely 100's of millions of people with some version Google Maps on their phones. How many just click through that one-time popup and forget it even existed (me being one of them)? How many even know what "in beta" means? My feeling is that Google has watered down the term to be meaningless.
Maybe it's generational. Once upon a time, "in beta" was called "in beta test", because that's what it was, a test, and what it means to me even today. Here's my recollection of the term:
When a product, not necessarily software, was considered functional enough, it was offered to a small group of people outside the development team. Those people were "beta testers" and were recruited, and well informed of, their function. The expectations were that they would give the development team feedback on flaws, bugs, functionality, etc., before the product was released to the public. The bonus for the testers was they got the product for free. Microsoft redefined it with one of their Windows versions. They widened the scope to the general public and I seem to remember they actually charged for the CDs. The bonus was the thrill of early adoption, the chance to brag to their friends, being part of a big thing, whatever. But they still fully informed the prospective testers that they had a job to do, and also had a cutoff number. It was still considered pre-release and not distributed in stores to anyone with a couple hundred bucks.
Now along comes Google, whose developers are often likely younger than my own kids, and therefore younger than the term "beta test". Some of their software is first released as "invitation only", but at some point becomes available to the world while still "in beta". This is hardly the secondary pre-release that meets the original concept of beta testing. Nobody is recruited for feedback (more on that in a bit), and the only disclosure that the software is in beta is one vague announcement the very first time you run the software. If they were serious in wanting to inform the user, how about the words, "Google Maps Navigation is in beta, and may not be fully functional. Please report any problems using the 'Send feedback' selection in the menu"? It's just text on a popup, so why not be more informational? Or is it there only for legal reasons? If someone uses Navigation and accidentally drives over a cliff, at least Google's lawyers can say, "Hey, it's beta - not our fault" to the next of kin.
So now I'm thinking (hoping) that Google is using a very different method for beta testing. Instead of actively recruiting a small(ish) group of beta testers and expecting a high percentage of feedback, they offer it to billions of users, many unsuspecting. They put in a "Send feedback" function. The strategy is that even if they see 0.1% response through the feedback option, that's still a huge amount of data. And maybe they even cruise the various forums for unsolicited feedback. If that's the case, then even the generic "me, too" comments could be of some use. While they seem annoying on the forum, making up probably 30% of the 250+ comments, they could tell Google that maybe they should have left the Navigation as its own app. And then they'll use advanced software to parse all that feedback and use the data to make the product stronger. Well, I can dream, can't I?