I’ve had nice 29er hardtails in recent years and my gravel bike does quite a different job for me.
On the hardtails, I’d focus on riding technical bits, enjoying singletrack etc. but on a gravel bike it’s just going for a ride, covering mixed terrain, exploring and enjoying the outdoors and the feel of just the air in my tyres between me and the ground.
I realise you can do that on a rigid HT, but for me the drop bars increase the speed potential so much, it’s an easy choice.
P.S. Something like the Boardman almost certainly wouldn’t be too heavy to enjoy.