It Might be Blasphemous

What it changes is how many ray receivers you can associate to a given sphere.

62.5MW is what a single ray receiver requests in photon generation mode. If the wiki is correct, lv8 on efficiency means the ray receiver is 83.9% efficient at 100% continuous receiving.

Thus the requested power for photon ray receivers at lv8 efficiency is 74.5MW compared to the 62.5MW its using or 12MW of energy wasted per receiver compared to the 0.3MW wasted in the image shown. My sphere, at 331GW, would support 4,443 ray receivers without the efficiency research (22,215 photons/m) but it can support 5,271 ray receivers with the efficiency research (26,355 photons/m).

It provides an indirect increase in photon generation in the sense that I can support 18% more ray receivers. It's probably not particularly relevant for giant stars or O-types but if you have spheres around smaller or less luminous stars then the research is going to make the sphere go a bit further. It's part of my strategy for deploying anti-matter fuel depots around the cluster as well as shortening supply chains for photons where I'm using spheres built only to provide just a bit more than what is requested.

The other thing is the research is cheap. It's only 46k for lv31 compared to the 512k I see for carrier engine 23 or 264k I see for VU 72. I would have to invest three more ranks to get it down to half a percent, seven more ranks to get it down to a quarter percent, and thirteen ranks to get it below a tenth of a percent.