Support stockings can help with veinous pooling in those with varicosities and prevent the achy feeling one gets from standing a long time. As was previously alluded to, these patients are also subject to poorer wound healing because the pooled blood increases tissue pressures in leg, thus preventing newer oxygenated blood from getting in. As a physician I sometimes see lower leg infections, cellulitis, ulcers, and skin discoloration as a result. Too much veinous pooling can also lead to decreased sensation in the legs, thus interferring with fine motor function and coordination. Some experts think that regularly wearing the support stockings can prevent the further progression or enlargment of the varicosities that usually occurs. An operation, in good hands, is probably your best bet, assuming you are a good operative candidate. In the meantime wear the stockings! Making sure they fit right and don't constrict in any one area.
However, independent of the veinous issues, there is an additional benefit to a tight fitting stocking or tights (or "skins") as studies have shown that the proprioceptive nerves in the legs, especially around the knees and ankles, can function more efficiently with an elastic wrap that hugs the surrounding tissues. I don't know the mechanism for this but remember reading this in the medical literature. This could lead to an improved sense of balance and leg/foot placement, thus improving skiing technique.

Ed