Hello,
Thank you 
The reason is only one: speed. SKU is in advanced window and modifying that field every time requires more time than writing only the code at the end of title (and if you have to modify SKU for each listing it’s easy to forget 
). So, just one example, I have 50 items from consignor X, I create the first listing with SKU=X, then cmd-D, cmd-D, cmd-D… 50 times, so I have 50 listing ready to be modified, but just title, photo and description and little else (like choosing the right shipping profile for weight). SKU is still X and I don’t touch it any more. I work with specific stock, so not 1 postcard from X, 1 book from Y and 1 coin from Z… I took all items from X and I do all. I know it could sound strange, but in my opinion it is the fastest way to list great quantity in less time possible (and also the easiest way to avoid forgetting SKU). That’s not all. When you have an order ready to be dispatched, it is easier reading title code instead of looking for SKU. SO difference between SKU and title code is: SKU for accounting, TITLE CODE for inventory.
Of course, we will do! Just an advice: write BEV as you did and then click on hand lens (just on the left of BEV). It should open a scrolling bar, choose SKU and it’s a done deal (I hope! if not, of course we will start another topic, but now it’s time to dinner for me 
).
Have a nice day/afternoon/evening (I don’t know which 
)