Use the I don't care about cookies extension its wonderful. Using it on my desktop and android Firefox.
This does not decline the cookies, it does whatever is easier
ITT a horde of people who don't know that http is stateless. Cookies are the easiest and least intrusive way to maintain your session.
Also an easy way to store needed variables between pages. For news sites without a sign up this isn't necessary but for actual web apps that live across different subdomains it can be a nice to have.
Minimal Viable Product?
Because your decline doesn't matter to them. They will track you even if you explicitly say NO.
