Using USSEP mod, it cured my frustration with Skyrim

Hi guys, just wanted to say that I installed the unofficial patch mod for fixing a truckload of bugs. I love it and cannot play skyrim without it anymore. It even fixed bugs I was so used to, I didn't even notice it anymore.

I see a lot of people stating bugs that could be fixed with this mod.

Main question: What is the reason not to use it?

It should not interfere with a lot of mods, and it does not fix the funny bugs in my opinion.

Side quest: I also wonder why Bethesda didn't reach out to the creators for anniversary edition or any other patch.