Coke cans were always a sign that the guy with the stuff was either not a regular smoker or was broke.
It was like the guy suddenly found himself in possession of some flower or hash and had no way to smoke it, so he had to McGyvver a can pipe.
TBH, I found the practice gross, as you often used a can you found in the garbage.
Much better to make one out of timfoil or, better yet, just have a chillum.