In my experience on spirited group rides, cassette spacing [typical of gravel bikes] can feel like a limiting factor. The ~17% jumps between teeth on a 9-speed 11-32 or 10-speed 11-36 or 11-speed 11-42 feel huge compared to the ~9% jumps on a "road cassette". Otherwise, road tires is all it takes to turn a gravel or cyclocross bike back into a road bike. I think it makes good sense to have two wheelsets for one split-personality bike.