I thnk you'll find that Rheem calls it Comfort contour.

The slow ramp profile is nice.
But with a humidistat, or thermostat that can slow the blower, VS blowers provide better comfort then the slow ramp does.
The slow ramp up waste time and electric on the hotter summer days, ramping the blower up slow, when it should be going to full speed quicker.

PS: A thermostat like the IAQ that can slow blower speed.is better then getting a thermostat and a humidistat to control the A/C.