For smaller systems, it is more effective for nutrient export to perform regular water changes as compared to skimming, since the number of nano effective nano skimmers are limited at present. However, for bigger systems, water changes can be tedious, if not, expensive, to rival what a large and powerful skimmer could do. Both has its pros that the other does not:
Water changes - replenishes trace elements and perimeters
Skimming - provides more oxygen
I would say, if it is possible, to incorporate both methods of nutrient export.