I always see a modulating headlight so, to me, they serve their purpose. They do stand out, IMO. Any time they've come up behind me I've never felt like they were emergency vehicles as if they were I'd be seeing red lights flashing.
***On a side note, a few years ago I got into it with an older female rider who said that modulators should be illegal as they could trigger her epilepsy seizures. I said WTF, a blinking light can cause you to go into a seizure? Then why are you even riding? What happens when an ambulance or police drive by you? You can crash yourself into innocent others. She got SOOO mad at me!!! I never understood her argument.