Sidelights alone are not allowed to be used in a moving car. Silly rule perhaps but that's the way it is.
I do agree, if you can't see an approaching car then you shouldn't be driving but that doesn't change the fact that many people do so, all the same.
They're often the same people who forget to light up when it's appropriate and necessary, or leave it until near darkness before doing so.
Automatic lights are there for these drivers.
But a DRL which is specifically designed to work as a DRL is fine. The idea is visibility, not vision and as such these lamps are designed (or should be designed) to provide a wide and diffuse patch of light, not a beam as such. I don't think glare is a problem. No artificial light is going to cause glare against a clear sky.
BMW also fits some ridiculously overly bright DRLs it's vehicles. At least Audi's ones are composed of clusters of LEDs.