what is so important about the sugar bowl

The sugar bowl serves as a McGuffin throughout A Series of Unfortunate Events. A McGuffin is a literary term for an object which drives the plot forward as competing characters vie to get their hands on it. What makes the sugar bowl, or "Vessel For Disaccharides," so important remains a mystery to the Baudelaire orphans throughout the series. There are hints that it contains something either very powerful or very dangerous.
Ultimately, the unknown contents of the sugar bowl do not matter to the plot. What makes the sugar bowl significant is that both sides of VFD want it and believe it is rightfully theirs, and yet neither knows its exact location. The sugar bowl has a long history of being stolen back and forth between sides. It is clear that Esme Squalor once had it in her possession and that Lemony Snicket and Beatrice Baudelaire once stole it. The Baudelaires also search for the sugar bowl at various points throughout the books.