So if you believe that it's fair to say that "people actually use Mastodon" (which has 1.5 million MAUs), then yes — people actually use Threads.
I felt like I had discoverability issues with Mastodon, and the culture I kept running into there was abrasive. It's all around much better now than it was years ago, and I do seem to get more engagement from strangers than on any of the other networks, but I struggled to stay interested.
Bluesky reminded me of the kind of slower organic growth that you'd typically find in earlier internet communities. The absence of videos and GIFs is, for me, an enormous positive point that I know will eventually give way to popular demand. I like that it's more text-and-images focused, and it seems to be in my sweet spot in terms of... most of what I see feel like thoughtful posts and replies, and not people nakedly building their personal brand.
None of them are going to have the same social cachet as Twitter. It's pretty incredible to see someone spend billions of dollars to completely squander an ecosystem an internationally recognizable brand like that. A fairly unique resource, obliterated by a man-baby with absolutely no concept of the value of the people on the platform he bought.
For now, it's the most viable alternative for Twitter - for now.
But this is in part because Mastodon UX is very complicated for beginners, and BlueSky is slow as hell to make improvements. It still doesn't support sending videos...
And it has reached the #1 position in most of the App Stores around the world.
Is it really no. 1 or nearby on Android ?