While the new setting will limit replies, it will not hide the tweet in question from those not permitted to reply, like what we see on Facebook.
They could still see the whole conversation, like it, retweet it, and see the fact that the original poster of the tweet has allowed reply permissions to a select group of people only.
Testing with a small percentage of users
The option to limit replies is being tested with a limited group of people - a small percentage of Twitter's global user-base - on Android and iOS.
However, there is no surety over the feature's widespread roll-out, as Twitter is still exploring how to give people more opportunities to weigh in conversations while ensuring more control at the same time.
Other Twitter features aimed at improving conversations