I think that increasing the word limit had to do with how Twitter has cornered its market.

People apparently crave longform content which is why you get like 60 tweet threads that are really just one article split into 60 chunks. Or people taking pictures of paragraphs and posting them. Twitter recognized that the change would make content more viewable.

The real issue is that people feel they have to get their longform content from Twitter despite the platform not being built for it.