Graphite works as an anti-static. It helps,
1) when snow is old (eg. dirty, oil from lifts and snowmobiles, tree sap and other junk),
2) crystals are abrasive (eg. new or man made snow),
3) when the graphite particles included in many graphite bases have fallen out through base wear.
Why not all the time? Graphite particles take up some of the space between P-Tex molecules (the so called pores) where wax would normally go. Too much of a good thing isn't good. Where "static cling" in snow conditions is not a concern then non-graphite wax works better.
Graphite impregnated sintered bases on brand new skis have only a small proportion of graphite in them to begin with. They don't need much, if any, more when new.
Graphite wax doesn't contain that much graphite, anyway. But graphite wax on new skis with graphite bases can actually slow the skis down (a little).
Graphite wax makes a good base conditioning wax for skis at the end of the season or for prepping skis at the beginning of the next season Note: graphite wax will stain clear bases but it is still a good conditioner.
Does all this matter? It does to racers and the difference is noticeable to many non-racers in the appropriate conditions. But of greater importance most of the time is having the correct temp. range wax on your skis. Some people ignore waxing at all
:and still manage to have fun.