I keep an eye on the day-ahead market prices (which determine the hourly prices for time of day contracts) here in Belgium.

It turns out that the energy price charged by a traditional contract matches the peak price of a typical day, plus a healthy profit margin. This makes sense because most electricity is consumed when prices peak.

So switching to a time of day contract does not actually raise your effective price per kWh, at least here in Belgium. Instead, it more or less keeps the same price for peak time, while giving you access to much cheaper energy off-peak.

I'm not expert in the system in California, but usually consumers are already paying the average spot price (plus some significant margin, which takes into consideration the demand profile of the consumer). Switching to spot pricing would not raise rates, and if consumer would adapt slightly to spot prices the average rate would actually decrease.