DRLs are a safety feature that puts the headlights on at low voltage (or a variant thereof), to increase your visibility for other drivers. Some makes use the parking lights, some use the high beam at low voltage, some use a separate bulb. The limitation is that the circuit doesn't include taillights, so I just drive with my headlights on most of the time anyways. It is a habit that came from living in the far north with lots of hours of dusk or darkness.

As an aside, could you please post your country in the user profile field? You make reference to it in your post, but apparently you live in X5world.

Thanks