Product managers execute the vision of the CEO and the company in general. Why do you think they don't deserve to announce something major?
Because this is more important than something you delegate. It's the biggest change to the company since the company was created. It's not like Twitter does 10 products, and it's like "bring Phil up to talk about this one". This is Twitter. If it was discussing random licensing deals with the NFL, fine, you can, and probably should, delegate that in order to signal its relative importance. But for this to be treated like something of that magnitude is wrong.
This is an experiment with a small group of users; it’s not affecting everyone.
Huh, I am in that group, and I have no clue how I got there, why, nor how do I get out.