It's has an abundantly iterator-based API, which is common in C++ but in my experience CGAL goes overboard with it which makes it hard to learn. I also didn't think it's well-documented when I was working with it between 2016-2018 as a computer graphics researcher. Maybe things improved. Great library overall, but definitely very fragmented and requires fair amount of reading to understand the API.
CGAL is a seminal library, but I agree with the parent's criticism of "fragmented" - for instance, the various sub-libraries have different licenses (GPL, LGPL, others), which may lead to accidental mis-use.
When I needed a few geometric functions back ~2005, I ended up implementing them myself to avoid a huge dependency on CGAL (the library back then was already bigger than my application) and the licensing implications.
