I'm off Twitter now, but I love the idea behind this, and would love if there was something like this but expanded.
One of the things about being on Twitter for a decade+ is that people change! There were more than a few occasions towards the end of Twitter where I had to stop and think, hang on, why did I follow this person again...? And then you realize, oh, they were a notable (person) in (field) six years ago but they've gone fully personal on this account. Or the opposite: they used to tweet really fun, offbeat jokes but now it's a professional account for something I would never have followed. I kept wishing for some sort of notes field to remind myself why I was following these people!