Then the checkmark can be used to bifurcate two social classes with different Twitter rights.
I believe Twitter has two types of content: PR and comments. The problem is they both look like tweets and have equal standing on the platform. PR is the valuable part of Twitter and comments are, well, comments. Most newspapers and blogs (the antiquated PR publishing mechanisms) already learned comments aren't worth the trouble. Now Twitter can make the distinction too.
For example, if you're not paying to be part of the influencer class, your comments could be hidden by default. The influencer class can also have a more stringent code of conduct, making it easier to ban people abusing their megaphone. All without stepping into 'free speech' debates with Incredibly Online keyboard warriors, who will mostly be on free accounts and themselves have what they deem to be 'free speech'.