Not everybody is fanatical about it. Some of us prefer open source software, but practically speaking wont use software that is straight up inferior. "What are the benefeits of this product over this other product" is always a valid question, and needs a better answer than "because it's open source." At least for me.
I'm not saying that cherry tree is inferior software, btw. I used it for like 5 years and loved it.
I use this one for all my work related notes. It's simply great. Unlike many other note taking apps CherryTree is not made with Electron. So it's both powerful and very light