Traditionally drawers were left unfinished (other than the fronts, which would be a show wood and stained and polished) with only a bit of wax on the runners. The reason was that (French) polish can taint natural materials with it's odour, whilst some non-polymerised oil finishes (e.g. walnut oil, oils containing raw linseed oil, etc) can turn slightly rancid in warm weather and can also sweat back into fibres such as cotton and wool (which is partly why your granny always used to line drawers with wallpaper roll ends, rear side uppermost). Wax can do this, too, if usewd to cot the insides of the drawers. Modern 2-pack catyalysed finishes overcome this, but leave the wood less able to absorb or lose moisture - so condensation inside a drawer (maybe because a dried item was put away too damp) is more likely to stay trapped there with slightly increased risk of mildew forming. This shouldn't happen in a modern centrally heated house with the RH is very low, but can still happen in older buildings with solid walls and wood stove heating, for example
