For the CX-5, this is actually huge. It instantly puts it in the best MPG for a crossover, at least until everyone copies it, namely Toyota in the RAV4. One of my gripes about the CX-5 is too many visits to the gas station and this or the diesel helps that. I don't really have major issues with speed, a little more 30-60 punch would be nice but it's not necessary. Of course, this being Mazda, it'll appear in the CX-5 around 2028, just after AA/Car Play in 2027 and 2 years after the diesel finally appeared. Instead they'll drop it in the 3 and sell 13 more of them.
For the rest of the line I don't know. This would take the 6, assuming 30% gains, to the bottom of the sedan hybrid market. Currently, there are 5 in the same class who tie or beat, in some cases handily, 40 MPG combined. So you still have a bumpy, noisy set of cars that get good mileage and can corner but not best in class if MPG is your criteria. The Accord Hybrid, the new Camry Hybrids are faster and the Malibu is I think just barely faster than the 6. If you drop a battery in the 6, and give it the CX-5 treatment, it's not a 6 any more, it's something heavier but it probably would get north of 50 MPG.
A 6 with the hybrid battery that is in the base 2018 Camry might be very interesting with this engine. You might be looking at 55MPG, even higher.
Now, if they can somehow sell the tech...