In fairness they're not meant to be essays - I think it's better to see these like a conference poster session, a small shop window of images and as little text as you can get away with to get across one or two core ideas about what you're doing. I do agree generally that Twitter is a weak academic argument format, but I have found MAMG quite a good part of it overall.
There will be a website where all the threads are compiled to some degree, I'll link that here when it appears - there are also thread readers available for cohesive-ising tweet thread.