I usually write notes on paper for _every_ meeting I have in my professional life. Even at meetups or other low-key situations, I will write down things before, during, and after.
However, I hardly ever go back and read them after the event. The point is not to keep a record of what I learned but instead to help me learn _in the moment_.
I have found that by hearing/reading something then creating a new thought/paraphrase of the thing I learned, then writing that new thing down, then reading what I just wrote all help solidify the new knowledge enough in my mind to not go back. I don't remember everything but I have the knowledge associated with other things enough that I can build on top of it, usually.
When I do go back, I hardly know what the notes mean and usually give up and throw the notebook out. The only common exception to this are action items/todos as I've learned to write those very clearly and with clear expectations.