Why do certain people add salt to their meal after it's cooked ?

My wife (55) adds salt at the table to every meal ( even on bacon ? ). I've noticed her mother does it and my patents also. I can't see the point of making any meal taste salty. Is this an age thing perhaps because salt was a precious commodity generations ago and this has been ped on - this is what I have heard ( I think..) Can you confirm as when I ask all I get is " I do it because I always have ". Thanks