The basic question is sound. "Theoretically", it should work. The devil is in the details.
A poor skinny LRR tire may have worse energy consumption than a fatter good LRR tire.
Same goes for handling, traction, stopping distance, and wear. There are a huge number of variables to contend with. This makes tire choice a serious challenge. It makes opinions very difficult to sort out.
I have a Leaf, but this is my experience with a Prius. 2nd hand car purchased with aftermarket set of 17-in Enkei RPF-1 wheels with Continental DW 215/45/17 summer tires. Car got about 43mpg, tires 'performed' well, but HOWLED-very noisy, to the point I hated them.
It also came with a set of OEM wheels with Bridgestone Blizzak WS80 195/65/15 snow tires. I put them on last winter. MPG went up to 47, noise decreased to acceptable, ride comfort improved. Never was in any situation where stopping/handling performance would be tested.
Normally I would not make noise a priority. I studied tire reports and personal reviews for hours. Opinions were all over the map. I finally went with General Altimax RT43 205/50/17, a bit skinnier, and taller. Tire rotating diameter almost identical.
Noise is comparable to the Blizzak's, acceptable. Ride comfort is a little better. Performance seems fine as far as I've pushed it, which is not much. MPG is a tiny bit better than the Continental, a tad worse than the Blizzak. In all, a satisfactory purchase.