I do exactly the same thing, using a tap of the regen paddle to cancel out of ACC. For me, it is less of a trust issue, and more that I like the way I slow and stop more than the way ACC does it.
I just tried it with Siri. She said: "Apparently we intelligent agents will never live that down.." Tried again. She said: "Without your space helmet, Tom, you're going to find this rather...breathtaking." Tried again. She said: "I'm afraid, Tom, I can't do that. Are you happy now?" Fourth time, she repeated #3. I told her, "Yes." She turned off.
Someone may have mentioned this in the 4 pages of posts. I have taken to keeping the max distance radar setting when up to speed so as to slow down earlier coming up to a traffic light where the vehicle in front is slowing down (maximize regen, minimum pressing the break). I will also reduce setting to 25 mph to slow down by regen if coming up quickly to the stop. Once at a stop, I set the radar distance to minimum. I find less delay in resuming ACC speed once the light goes green/break lights from the car in front goes off.