The most important benefit of vitamin C derivatives is that they are much gentler on the skin as they don't cause irritation. Another notable benefit of vitamin C derivatives is that you can use them together with other active ingredients. For example, while it's almost impossible to use a pure vitamin C serum together with an exfoliant like glycolic acid, you can use an ascorbyl glucoside serum or 3-O-ethyl ascorbic acid serum together with other active ingredients without irritation.