Opening a plastic bag is frustrating. The 2 ends stick together stronger than a superglue and no matter how much you blow, rub or curse they don’t separate. The productivity and the temper at the restaurants and take-away counters could be reduced substantially if the daily battle to open a plastic bag be reduced from a 30sec 2 hand chore to zero.
At Seven-Eleven Shanghai they use a unique fold top sandwich bag. Nothing rocket science about it, one end of the bag is folded to make a sleeve hence preventing the vacuum lock that makes packing an excruciating exercise. Also there is a lot of convenience in eating because the flap (other end) floats underneath your sandwich and protects your shirt from the dripping sauce.
BTW I am yet to find a single convincing answer why Indian government has banned plastic bag less than 30-50 microns. Thicker plastic is no more environment friendly than its thinner counterpart. But it surely is bulkier making it more difficult to recycle (per bag)