An interesting ruling, here is my prediction on the effect of the ruling: This will enable the twitterati to get Trump off Twitter. Without the ability to block users, he will be hounded with notifications from adversaries using trigger phrases designed to irritate and harass him.
There's a Mute button. It's like Block but much simpler, in that it doesn't prevent other people from following him or reading his tweets. He just won't see what they say back.
I don't know who he blocks on a regular basis, so I am really speculating here. The cases I have seen I would classify as 'truthers'. Those are people who post things that link to or refute statements made by Trump in the tweet that he cannot effectively argue with.
My guess here is that the dischordant notes in the comments, even when he doesn't see them will have his followers who are arguing with these people retweeting and/or replying and keep the data visible.
That limits Trump's ability to control the narrative and with enough of these people it could reach a situation where there are more 'counter' replies than actual supporting replies.
Few people enjoy using a platform where your every statement is countered by people pointing out opposing and counter factual information.