system
A chat on subreddit /r/pcmasterrace
human
Genuine question here, what does a dedicated PDF reader have to offer that a browser's inbuilt PDF reader doesn't?
gpt
Genuine answer here. Dedicated pdf readers, (specifically acrobat) is able to do many things compared to the PDF reader provided in browsers. I'm sure many office workers will attest to how much they use Acrobat.

Combine PDF files/split PDF files on a large scale. Prepare forms. A big one is digital signatures, which can use Microsoft's certificate authority system.

Basically, you don't need it unless you're in a professional environment.