It might be possible to find conflicting opinions on any topic on the internet, especially those that are in doubt.
You might want to look at the tread patterns of tires that are designed to result in less rolling resistance. Search words could be “fuel saving tires” or “low rolling resistance tires” to see if there is anything unique about the siping of these tires. I took a quick look at the Continental Touring Contact AS tires that are on my Chevrolet Cobalt XFE that is dedicated to good fuel mileage with a highway rating of 37 mpg which I can exceed in the summertime. These tires have some siping; not a lot and the siping is limited or closed in that it does not extend to the edges of each tread block. Tire Rack has a selection of low rolling resistance tires but I did not see mine in the Contintental selection.
My tires, by the way, have poor traction in the snow; not surprising that the design was compromised to more heavily favor another feature.