Of course both are the most important because gambling is a game of probability, so luck and skill are really needed.
I actually often pay attention to people who only gamble using luck alone, to be honest they will definitely lose, they don't know that the skill factor also influences winning when gambling.
Of course you are right, gambling requires both luck and gambling skill. If you have enough skill in gambling but if your luck does not favor you then you will lose the gambling game and if you only depend on luck then you will surely lose your gambling game. Skill in gambling helps you to take right decisions while luck helps you to win in gambling. Gambling skill is the first and very important step because if we make a mistake in the beginning we will lose the gamble even if luck is in our favor. So first we have to make the right decision then it is a game of luck. If we lose a gamble even after making the right decision, we have to accept that our luck was not helping us that day and try again later but with the right decision.
We just have to go for the two because they are all very important, sometimes one cannot exist without the help of the other, if we look closely to how gambling is, we will noticed that none of the two can go without having the impact of the other for it to succeed for our own benefits, even when we realized that we are the type of gambler that could need gambling for having fun for this purpose, we will still need one of the two to achieve our goal with gambling.