Usually, oak chips are using during initial alcoholic fermentation. At later stages, larger forms of oak (cubes, beans, spirals, etc.) are thought to be better. I do not know if that is true, but that is what many people assert.
This is my take on chips vs. other oak products:
Surface area matters. Wine contact with the surface area of the oak product determines (to a great extent) the amount of leaching of oak character into the wine.
Cubes, spirals, and staves each have a consistent surface area, which may vary by manufacturer. Cubes are the least consistent as not all cubes are the same size, but overall, when you put in 2 oz cubes, a spiral, or a stave, you have a good idea what the outcome will be based upon batch size and length of aging time. Note that each type may produce different results, but when you put in X amount of cubes in Y amount of wine for Z days, the outcome is relatively consistent.
Chips? The surface area is probably un-calculatable. A bag of chips has all shapes and sizes, so there is no way to guess at the total surface area. All you can do is taste periodically and remove the chips when satisfied.
While this is also true of other oak products, when I add 2 oz cubes to a 5 gallon carboy, I have no concerns about not touching the wine for 30 days as I know it won't be overoaked
IMO. [Personal taste is critical.]
OTOH, fermentation is a short period which limits oak contact (4 to 10 days). This isn't long enough for cubes, spirals, and staves to make a enough of an impact. The large surface area of the chips works in the winemaker's favor during fermentation, as more oak character is extracted in the short period.
There are probably other factors, but surface area is an obvious one.