Those are a lot cheaper than my Denali D2's >_<
As for dimming I would never dim during the day. When I drive my car I even turn the high-beams on during the day since I rarely use them at night. For my bike the high-beams are also on during the day. I like to stand out.
Keep in mind my headlight is low beam only. If you ride your bike with your high beams on that means your low beams are off. So with my setup you could leave the aux lights on during the day since those are technically the high beams for this setup. (2x 10 watts so it's still way more efficient than the stock halogen(and brighter; each aux light is 1,000 lumens))
It's nice to have the low beam turn on and off automatically to save on power (and i guess increase lifespan even though I doubt the lifespan of an LED will ever be an issue lol) Plus, the low beam hardly makes the bike more noticeable during the day anyway. The whole point of projector housings are to reduce glare.
I personally only use my aux lights if there's limited visibility or when I want to flash them at people who cut me off.
I do agree that Daytime-running-lights improve safety and there's a lot of data to back up that claim. That's why I have the LED ring as my DRL. It's more efficient than the low beam AND appears much brighter during the day. So that's why I want low beam off and DRL on during the day. I want it all automatic so I don't have to mess with flipping switches.
Lastly, I still have my aux lights as a reserve to flash them at people during the day.