Good luck is accompanied by good luck.

"Good luck" and "good luck" have different meanings. The main differences are:

"Good luck" means that when experiencing some ups and downs in life, good luck is always around or accompanied by good luck. It mainly emphasizes the time node of good luck and its comforting effect on people's hearts.

"Good luck is with you" means that good luck will always be with you and will not leave, mainly emphasizing the state that good luck will always exist.

In a word, both of them express the existence of good luck, but the emphasis is different.