Okay, that is just wild, I mean - what are the odds? lol
Growing up, I really just thought it was something my family did and as an adult I didn't really think of it at all, ever. But now, I'm super curious about how common this is and why. I guess this is just one of those things that is so common that no one really thinks about it until it's pointed out. Now that I am thinking of it, I did a bit of googling....
The basic gist I got is that since most packaging is made to be disposable, when these tins were first released (at a higher price) and people purchased or received it as a gift, it felt too wasteful to simply toss it out after it was empty. And then there's the fact that wartime mentality had households trying to reuse as many items as possible for as long as possible just makes it all the better to any household consumer who had still had those thrifty habits.