Is it a quirk of translation?
First, it's not really a quirk of translation, but it's possible that the word for "honey" refers to date honey, not that of bees. Many references in the bible unambiguously involve bees, but other Semitic languages use the same word for both types^1 . Additionally, later Jewish texts (the Talmud) seem to think that bees don't make honey, they collect it, so perhaps regular honey and date honey would've been thought to have been the same substance^2 .
Anyway, both items are used in the bible in other idioms. Honey is often used as an idiomatic "sweet thing"^3 . Milk is somewhat less common idiomatically, but represent a generally tasty beverage whose abundance is symbolic of general bounty even when not paired with honey^4 . Together, using these two foods as the representation of a land that's rich makes sense given use of two as idiomatic foods.
Sources:
I hope it's alright if I add a question, if not feel free to delete.
According to Zonaras' account of scaphism, the condemned was force-fed a mixture of milk and honey. Aside from the practical effect of this mixture attracting insects, did the specific use of milk and honey, given its idiomatic meaning, have any symbolic/"poetic justice" connotations, e.g. executing a greedy general with molten gold?
I apologize as I do not have a historical background for this particular question, but I do have an animal husbandry background and have a possible explanation.
When weather is good and conditions optimal, both bee hives and cows will overflow. Hives will drip honey and cows will drip milk from their teats. Both occur only in times of good weather that promotes an over-abundance of flower bearing, fruiting plants, and ample lush grass and really occurs in only very fruitful agricultural areas with plenty of rain and rich soil. But when conditions are right, both hives and cows will 'overflow' with overproduction. So one possible explanation is that is a very literal description of Canaan being a land of plenty by describing both milk and honey as 'flowing'.