These clever insoles are sized to the arch of your foot. The theory is that supporting the arch of the foot increases power transfer and comfort.
As you push down on the pedals you are stretching the tendon in the arch of your foot which can lead to foot pain. Supporting the arch alleviates this problem.
We had this exact problem with a pair of stiff-soled SPD shoes, but once we inserted these the hard plastic support effectively banished the problem completely.
It’s too difficult to say if power transfer was up, but we were happy enough with just losing the pain.