The pink ones have lovely, flat, translucent, papery seed pods in the autumn. It appeared in my utterly unsuccessful attempt at a woodland garden, under some trees where nothing but weeds grew. It follows the few snowdrops, and holds its own against cleavers, so it can stay!
The white one also appeared by itself, but it grows in several places...so I'm suspicious of it. The leaves are a paler, slightly yellower green than in the photo.