I like flares for gravel/adventure riding. Wider hand positions on the drops allows more stability at speed over loose conditions while staying low. Additionally, the larger number of hand positions helps on long riders. The right of this photo is my drop-bar Pugsley with Woodchippers - I've used this bike for rides up to 140 miles in a day.
2017 Flithy 50 - Photo Credit Mark & Laura Broadwater