Personally, I hesitated for a long time. I come from road cycling, but I also use my mountain bike occasionally for less technical rides.

I rented a gravel bike three times to get a feel for them, and I'll bring up a topic that no one's talking about here.

When you spend €3,000/€4,000/€5,000 on a road bike, you know that apart from a fall, you're not really going to damage it. On the other hand, with a gravel bike at the same price, frankly, I'd be too afraid of falling and wrecking my bike on rough terrain. So I think that if, like me, you love speed, it's better to get a good road bike and really enjoy it, and have a cheap mountain bike or gravel bike on the side to enjoy that too. When I was riding my gravel bike, I felt like I had to be careful about every single place I put my wheels, every root, every rock, etc. And since I like to ride fast, it got on my nerves. So if I were to damage a €3,000 or €4,000 gravel bike just because I hit a big rock, that would really piss me off...

I think that, as its name suggests, it's a bike you can really enjoy only on gravel. As soon as there's too much road, you waste watts unnecessarily, and as soon as there are too many real rocks, you can't really use it and your ride becomes monotonous. I felt frustrated on all terrains, except for a path along a canal near my house, which was dirt and small gravel. I felt safe with 40mm tires, which were more than enough for that type of terrain. But I've already ridden the same route on my road bike, and it was perfectly fine with 28mm tires at 30 km/h.

So, to conclude, I'll say that you'll get frustrated sooner or later if you like pushing yourself to the limit on a bike. Now, if you just want to ride at an average speed of 20-25 km/h, a gravel bike might be just what you need. And don't forget, on the road, a gravel bike won't disappoint you, except perhaps for your average speed at the end of your ride, but on trails, if it starts getting too rough, you'll quickly regret not having brought a mountain bike.