Android Messages is apparently [1] the renamed "Messenger", the Google one (the internal android APK names are the same), which was probably confused with "Messenger" the Facebook one, likely to Google's detriment and Facebook's gain. Renaming it probably salvages some of that confusion.
Also, Hangouts "the original" (aka. the Hangouts App, Chrome Extension, Chrome App, Gmail Widget, and the standalone website) -- most of which will probably live on. The extra irony is that the same time Hangouts App users are being warned to move to a different app for mobile text messages, GTalk users are being told to switch to Hangouts, while Google Voice users are being assured that their Google Voice texts (and presumably calls) will keep working within the Hangouts App, even though a new Google Voice App was recently released that mysteriously added chat.
But Facebook Messenger now wants to eat Snapchat's lunch and is offering Snapchat functionality. Great, that annoying cat lady who I'm "friends" with now can spam my Messenger app with pics of her cat. And I shared a picture with a friend and Messenger suggested I posted it to it's NotSnapChat. It's a single button inside the chat bubble, which makes me wonder if the publishing happens directly when I push that button, and who'll be the next Anthony Weiner after he accidentally presses that button...
I downloaded Facebook Messenger Lite and highly recommend it. It strips out everything except... well... Facebook Messenger. I can message people, and there's none of the extra UI crap, including their Facebook branded Snapchat copy (not to be confused with their Instagram or Whatsapp branded Snapchat copies).
Officially it's only supported in emerging markets, but you can download it from apkmirror and it'll install just fine.
I've thought about this, too. All the chat and social network tools are constantly shifting their UIs and naturally, I guess, trying to highlight new features, which on a tiny phone screen is equivalent to making them easy to accidentally click.
The worst I've done is accidentally send a Facebook "thumbs up" in an inappropriate context, but it's easy to imagine how you could do much worse.
In my experience users don't know or care to know the name of the product they're using beyond 'google'. If the app has their friends and contacts in it and people respond to messages they'll use it.
If I ask someone what app or service they used to send me a message I didn't see, they can't really tell me.
Increasingly they don't even know if they sent a text message or something else entirely.
If you're a Project Fi user like myself, you have all access to all of these technologies. All you need to do is pressure your friends into joining Project Fi and they'll be able to chat with you too!
Hangouts Meet and Hangouts Chat are part of Hangouts realignment to be enterprise-focussed, and are, IIRC, only available as part of GSuite. Users don't choose them, admins do.
Android Messages is an SMS-only app; your device vendor probably has their own default one, but if not (or if you don't like it) you can use the Google one. (It's not that new, it's been around since about the time they announced the new direction for Hangouts, long before they implemented the new enterprise-focussed Hangouts offerings.)
And GTalk is being buried, so isnt really an issue.
- Google Talk
- Hangouts Meet
- Hangouts Chat
- Android Messages (something new, never heard of it)
(And non-google messenger technologies: SMS, RCS).
How user is supposed to navigate all these? Given that all these things are inferior to even Facebook and is ICQ-grade.