600Wh means it'll provide 600 watts for an hour. It'll provide 1200 watts for a half-hour. It'll provide 2400 watts for 15 minutes. Or it would if it were linear and batteries rarely are. It's a guideline, though.
The iPhone 8 plus has a 2675mAH battery. It runs at 3.7V. That's basically a 10Wh battery. Opportunity is basically 60 iPhone 8 batteries.
Your Chevy Volt has an 18kWh battery. Your car could power 30 Opportunity rovers.
House voltage can provide 115V at, typically, 15-20A. As a consequence most commercial appliances top out at 1700-1800W. You could plug 3 Opportunity rovers into a single circuit before you blew the breaker.
A 4x10 bass cab rated at 1000W peak prolly pulls down between 1200 and 1500 W. Two Opportunity rovers would rawk as hard as a single 4x10 bass cab.