This is where I take issue. Messages is completely inferior to competitors like WhatsApp. Using on your laptop? Everyone has that now. There is nothing that messages has that it's competitors don't. What's something that the competitors have? They work everywhere! Which is the most important part of a messaging app. If half your friends can't use it (which is statistically likely, unless you only make friends with people who use apple) then it's useless.
There is nothing that messages has that it's competitors don't.
The combination of: wide acceptance + an owner who is not incentivized to use your chat (meta)data to sell ads. That is something for a platform we use to share very intimate conversations.
Sure, there is Signal, but it is far less widely used (at least among my friends).
And then Messages has some very nice platform integrations, such as: Continuity, fill 2FA codes from SMS received on your phone into a web form on your Mac, animoji.
Messages works with SMS. As far as I can tell, WhatsApp doesn't. That's a HUGE difference and definitely what I would call "wide acceptance". I can text my grandma from my MacBook via messages. Good luck getting her into WhatsApp.
You're talking about iMessage. Messages uses iMessage AND SMS so it is a tool I can communicate with everyone without them needing to install anything or have any kind of account.
The ubiquity and integration with the OS is unlike anything anywhere else. Every time I've tried to use Linux/Windows/Android it's the killer feature that brings me back.