Here is a quote from Bike Radar that amused me and slags both us old school mtb'ers and the new school Gravel bikers off with equal comedy:;
"A gravel bike is a road bike, but heavier and with slower tyres. It's narrow and steep and tall, and you can't shift your weight much, so it teaches you ancient, authentic skills such as 'desperately trying not to crash' and 'how to still crash' and 'acting superior even now you've crashed’. It's just like mountain biking used to be, before it was ruined by marketing BS! And quantifiable progress! And by, you know, physics!"