“no advantage to having a charmer.” If the snake bites before the charmer arrives, then then there is no profit in calling in a snake charmer. But some versions interpret the verse as saying that if the snake bites before the charmer arrives, then there is no “profit,” no money, given to the charmer. This verse about snake charmers is likely in Ecclesiastes because snake charmers were thought to have a special wisdom that allowed them to charm the snake, and wisdom is a major subject in Ecclesiastes.
“charmer.” The Hebrew uses what seems to be an idiomatic phrase to describe a snake charmer: “the master of the tongue.” In Akkadian, the “master of the tongue” was a person who spoke many languages.
The King James Version sees a different meaning in the verse (although they did not have access to Akkadian at the time) and takes “the master of the tongue” as a babbler, and like the snake, he will hurt you if you do not “charm” (pacify) him. Choon-Leong Seow (The Anchor Yale Bible: Ecclesiastes) notes that the Sage uses the phrase “master of the tongue” to refer to the snake charmer but notes that he likely uses that unique phrase in order to make the bridge to Ecclesiastes 10:12-14, in which the mouth and lips of the wise and fools are focused on.