If the weight saved is worth the investment, go for it. Personally it wouldn't be for me. It's the combined weight of bike, rider and gear that has to be moved, and I feel there are other areas than handlebars, stems and seatposts where more significant weight might be saved.

The rolling resistance of wheels and tires plays a part as well, though I prefer "bombproof" over minor weight savings.

On the road after stocking up on food, fuel and water, thinking about the saving of a couple of hundred grammes (basically one banana more or less) here or there seems pretty irrelevant, but hey ymmv