They might not need to now, when most energy is generated by systems that run around the clock. But as we generate more solar, it'd be great if people could run more of their high energy activities like say, car charging during the day. I don't know of any way to incentivise this behaviour other than pricing.

Of course it's unreasonable to expect people to monitor prices on a minute-by-minute basis. But the future probably looks like "oh, car is low right now. I'll plug it in this afternoon instead of right now".