Modern computer security is about removing as many known possible attack vectors as possible.
So that's the benefit.
EDIT: to those saying browsers are sandboxed or that there's nothing sensitive, it projects against e.g. Comcast injecting JavaScript into pages from other sites. [1] There are all sorts of types of bad actors out there. Surely I don't need to list them all here.
[1] https://thenextweb.com/insights/2017/12/11/comcast-continues...