8ball
Decolonise colons!
In general, the blue paint superhighways are little better than useless. However the bit at Elephant & Castle is ok, cos it takes you round the back of the two major roundabouts through quiet backstreets and cycle-only tracks. There's even some separated lanes in places. As Crispy says, it's slower, but much safer and more pleasant.
Some of it can be seen on this video:
So I guess 'it has its uses, in places' would be a reasonable summing up?