One reason I know is because the dealer only bags it with plastic from a shopping bag once he is at the location and about to sell to you. Reason for this is if he gets stopped he can plead personal use for a half ounce of cocaine if it’s all in one bag versus 14 separate baggies/has baggies and a scale on him. Someone in the game for long enough will be able to just eyeball his bags as he is on his way to chop to his next custy and by using plastic just from a grocery bag he can easily plead not guilty to dealing as he won’t have any other dealing related baggies on him and can say, as I already mentioned, that it’s just for personal use and he has a coke problem lol.