Yes that does get you 99% of the way there at least. It does require predicting/assuming the electricity prices though. If they are predictable enough, that's fine. It doesn't quite reach feature parity with actually fetching electricity prices every hour and slowly learning when it's cheapest over many weeks.
Not sure how much prices can vary over the day, and more importantly how that varies by weekday, season and so on. How much you can make by having an online price service varies with how well you’d be able to “hit” the price dips manually too.
