The number 7 is seen as lucky in slots and pop culture because it’s been a...

https://ellasbestdigests.theglensecret.com/what-does-it-mean-when-a-slot-uses-metallic-sevens

The number 7 is seen as lucky in slots and pop culture because it’s been a symbol of good fortune for centuries. Classic slot machines often highlight triple sevens (777) as top wins