We rely on salt for flavour. It is a wonderful substance!
When you salt your steak earlier enough, you are giving the salt time to actually go beyond the meat surface to reach deeper into the meat’s interior.
I try to do this 3 hours to a day before I cook steaks. During this time frame the salt flavours the steaks throughout.
When you first apply the salt on the steak’s surface, moisture does appear on the exterior but over a period of time that moisture gets reabsorbed back into the meat. So salt is actually keeping the meat moist as well as flavourful.