I've got to admit my first reaction (as a non-twitter user) was "wait...you mean this stuff wasn't already in it?".
Perhaps it's self-explanatory, but I'd still like to know: can FOLLOWERS still see what others reply to the original tweet? In other words: say I tweet something, and person A replies with something I don't like (say...completely proving I don't know what I'm talking about). With this new page, I can put A's reply to another page where I can still see it if I click some "hidden replies" thing.
However...when person B sees my tweet, can (s)he also see A's reply? Meaning: is that "hidden replies" thing equally public?
That's the grand crux. I'm against it if it's not, but to be honest...I don't see the point of the feature if you can't use it to, y'know...censor.
BTW: I'm a member of a different feature that grants such censoring power. One of the fastest ways to destroy your reputation there is by attempting to use it. All it takes is one person to realize their response is being removed. Said person simply states this and takes a screenshot. Once the OP attempts to censor this as well, the said person just uploads the screenshot as picture, and then replies again with the link ("hey...why did you remove my last reply (insert image with last reply) ?"). More often than not, friends pick up on this and join in on the discussion. The end result is usually a thread with one (often almost childish) controversial statement and multiple pages of dumpster fire. Because no matter how much you can censor: you are still one person. In the end, you simply cannot censor faster than people committed to disprove you.
In addition to that: you can't censor an opinion without spending time and attention to it. So I wonder...how long before Trump will give up blocking replies he won't like because there's only a finite amount of time you can devote to twitter censoring?