I think they are both needed in trading we need skills to trade bitcoin or altcoins and we need luck for we have get a big profit in trading so we need that both in trading industry for to make income in bitcoin.
Both are needed to have extraordinary profits from trading. But to survive in trading we just need skill. Only skill will be enough to earn decently. I am experiencing this in real time with my trading daily. I do not believe into luck and I am able to earn a living with my trading.