It helps if and only if the glucose stays as glucose and is not metabolized. Wood is a good application of this, as its cellulose fibers are made of glucose, in a form that is very stable and can stay locked away for a long time (especially if the tree is alive as it does not metabolize the glucose in its own wood and has anti-predation adaptations that actively guard it against other organisms). However, if the glucose decomposes, i.e. is metabolized, it is converted either directly to CO2 or into other compounds that eventually end up as CO2, essentially returning the captured carbon back to the atmosphere.