There's so much valuable research that can be done with aggregate Tweets that you can't do with just lone accounts. For example I've seen flu outbreaks being predicted by hashtags. (http://money.cnn.com/2017/05/11/technology/tracking-flu-twit...) The possibilities are really endless, but depend on whether you have the data and whether it's over a large enough timescale for your use. Twitter represents a large portion of our culture and just because you don't personally like it or have a use for it, doesn't mean we should just throw away archives of it.