When a reward comes on the screen and you activate it using the space bar, I can honestly say I have no sensation of the affect I would have thought it would give
For instance when I activate the feather on a steep climb, I expect the resistance to get a bit easier. If I activate the aero feature I expect to feel peddling a bit easier.
Then there’s drafting, I never feel any benefit.
Am I alone in this? I’m using a Kickr, what do others feel on other trainers?
I do notice the effects. The aero lid boosts speed by around 3mph, the feather does ease the climbs (just) and the draft is more pronounce.
They are not designed to be huge benefits though.
That being said I would rather they weren’t there.
I’m not sure that the powerups affect resistance. I haven’t particularly noticed the resistance decrease using the feather on the hill (although speed does go up significantly). I suspect this is not implemented (yet?).
Take it from Greg Lemond - “It never gets easier, you just go faster”
I don’t have a computrainer or Kickr, so no feedback for me. But watching the power, I notice it takes less to draft for a given speed, and also that there is less draft benefit on the climb. There is no feel anything for me, using ANT+ power or my Kurt Kinetic, but I can also spin 175 Watts on the climb if I want.
I’m thinking you would feel them if you tried to maintain a constant speed. The feather makes your w/kg go up and therefore you go faster up a hill at the same power. If you backed it off to the same speed you were at (on the same grade) it would feel easier because you would be putting less power into the pedals to maintain that speed. Same with the Aero powerup except it changes your calculated drag coefficient rather than increases you w/kg.
However, I try to keep the same power (or more) and go faster to take advantage of the powerup. 
What I mean is that if they were adjusting the resistance on smart trainers cadence should go up with the powerup if you maintain constant power. I don’t think this is happening right now. The only effect seems to be on the in-game speed.
I don’t think they are meant to affect your power output. They just give you a speed boost on screen.