Equity has no intrinsic value and I'm glad you recognize you can't pay rent with it. Founders who try to claim otherwise are being deceptive and I wouldn't work for them either. Much worse if you get insulted and called an idiot for trying to negotiate.
However, equity is a significant form of compensation, not just at startups, but at large companies as well. You're missing out if you don't take some time to understand it in early stage startups.