Well, when I replaced my T5 with 275w of COB for veg and I took down the 1 HPS and put 600W of COB's I was able to turn off my portable A/C in the grow room period. It's in the garage I put a rack in place to hold my supplies lol. With the old setup that unit ran all day at 73 degrees or so, plus the house A/C had to be set cool all day running. Now I just run the house A/C as normal and there is still a 1K HPS in half the tent. So the temps can only improve when/if it comes down after this run, we shall see. But it's looking like it's coming down lol.....
Now I can run my exhaust fan quieter too, going into the grow room does not borderline require hearing protection lol. That's why I built my COB lights with passive cooling in mind got tired of all the damn fan noise. There is also no U/V in the COB's lighting to worry about when working under it. Mess around and work under an HPS for too long and see what happens lol, sunburn!
These are the major things off of the top of my head but there's more I am sure.
But, at the end of the day lighting is but a part of the equation, your room/area as a whole needs to be dialed in. Environment plays more of a role. The guys that are good, can grow under anything.