I think your answer is in the title. I'm not sure how concrete you want to go in terms of answers? The reason you should is mostly constituted from all the thi

I think your answer is in the title. I'm not sure how concrete you want to go in terms of answers? The reason you should is mostly constituted from all the things your browser does that you don't know about. I get that's a hard sell. Firefox is (currently) measurably much less binary exploit secure than Chrome, but it is the browser with a development community thats trying hard not to sell you out.