I asked my Service Manager the same question and his response was the eTorque system helps keep you in 4 cylinder (ECO) mode longer. I wasn’t certain he was correct but my eyes and butt don’t lie when running in ECO mode. So, I found the following which also appears to indicate there is a correlation between the two systems.
“As it has been for many years, the HEMI V8 is equipped with a cylinder deactivation system that can shut off four cylinders during light load conditions. However, since most roads aren’t completely level, the engine often ends up cycling back and forth between four and eight cylinder modes.
With the mild hybrid system, the BSG can give the engine enough of a boost on gentle grades to keep the engine in four cylinder mode to keep the other four cylinders shut down.” In simple terms, it may not keep you in ECO mode longer in the Rockies or the Texas hill country but it does help you stay in ECO mode longer in the flats like the Gulf Coast.
www.forbes.com/sites/samabuelsamid/2018/08/24/2019-ram-1500-etorque-getting-mildly-hybridized/amp/