I agree. I occasionally turn to them to see if they work in a new setting, but find they never expose the features of a grid I would find useful. Everything must be manually placed, rather than allowing content to intelligently snap to multiple axes. Possibly I never have grasped some fundamental concept, possibly they are not suited to the sorts of layouts I usually work on. But more and more I feel they are designed to fulfil some purpose orthogonal to what I would need them to do.