A gravel bike will typically give you a more upright riding position than road bike geometry, with a longer head tube and shorter reach. That should result in more comfort on long rides and also lets you shift your weight around to tackle obstacles and off-road descents
Gravel bikes have a snappy-yet-stable character that mixes cyclocross and road geometries. A relaxed riding position, longer chainstays, and larger tire clearance all contribute to a smoother, more comfortable ride.
To accommodate needs on long rides, many gravel bikes include various mounts to attach feed bags, additional water cages, or lightweight bikepacking gear.
Some new frame designs allow for easier wheelset swaps. Run your lightweight 700x25 set for road rides, then switch to an off-road set for weekend getaways. Enjoy both riding styles with just one bike.