Twitter likely uses content-editables over input elements because there are certain features which require more complicated, dynamic rendering than just plaintext (hashtags, mentions, links). They probably even have a team of frontend developers dedicated to this one thing. Rich text editing on the web is something everyone, not just Twitter, has trouble with, specifically when dealing with mobile, with IME, or copy-paste edge cases. I get your frustration, but know that this is one of hardest problems remaining in modern web dev, and it’s a feature which is expected by the majority of users, who don’t spend their days editing plain-text files. I do think it’s funny that you opened a web inspector, saw the divs and spans, and decided to get mad about that.