This comment basically sums up the reason for doing this.
That's quite the interpretation. Let's look at another example of the grandparent's point. Recently, my city had a smattering of freezing rain. Not enough to cancel work for most people, but enough to make the roads *extremely* dangerous.
As it happened, the heater in my car broke shortly before the freezing rain, so my defroster didn't work below about 15 MPH. Traffic was moving at a brisk 1 or 2 MPH for many miles as we all made our way home, with cars forming a densely packed block on the road for a couple miles. Visibility out of my windshield was extremely poor, so I had to navigate largely based upon the appearance of the white center line and side white line.
Even with those driving aids, it was difficult to stay in my lane. And that's not even counting the frequent minor slides along the road when everything was going otherwise perfectly. The white lines were the main reason I was able to make it home safely.
That being said, the U.K. is not the U.S., so white line removal may make more sense there. But for most places in the U.S., that would be homicidal.