From these pictures you can see that the stones of the White Moss Circles are no larger than those of Bratts Hill. Both have central cairns, neither are all that prominent.
The central burial feature, common between all five circles on the moor reminds me of pyramids, sacred burial places, somehow hallowed by the stones. This is not a universal use for stone circles by any means, many have no signs of burial in or near them. It was certainly one function of the Burn Moor circles though.