Longhand notes (which I do frequently for the RPGs I run, so practice isnt the issue) are nigh unreadable. I literally have dozens of notebooks (not full, but at least 30 - 50 pages each is pretty common ) of notes I struggle to read and organize.
Being able to write with speed and br able to read them is why an elementary school teacher recommended that I try using a computer to write on back before laptops were a thing, and it remains a big reason I rely on them for work notes now.