Well, most couples would share one bag, and in this context specifically, it would also be awkward wording even if that’s what they meant.
In the first panel he cashier is asking if they want ‘them’ salty or sweet. Indicating that contrary to what would be common this couple has, indeed, chosen to buy multiple bags. Perhaps there was a special offer making it make far more economic sense to have separate bags on the occasion.
That’s singular, though. If you’re talking about two bags of popcorn, how do you refer to them?
Well, most couples would share one bag, and in this context specifically, it would also be awkward wording even if that’s what they meant.
But yes you could in some context obviously also talk about bags of popcorn as “them”.
In the first panel he cashier is asking if they want ‘them’ salty or sweet. Indicating that contrary to what would be common this couple has, indeed, chosen to buy multiple bags. Perhaps there was a special offer making it make far more economic sense to have separate bags on the occasion.
And at the same time they aren’t referring to anything individual about them. Struck me as a non native English speaker writing a bit improperly