That's a perspective I haven't heard before, though I see that Google somewhat agrees with that being a valid point of view. Though it does suggest higher speed with more intention is a distinction. In my mind, hiking is something I do on a trail. I walk around my neighborhood. This includes a couple of climbs of ~200 feet over the space of about four city blocks. Moderately steep, but entirely normal terrain for the area, and all on paved roads or sidewalks at ~3 mph. Never occurred to me to think of it as anything other than a good walk.

I walk for 1hr on a treadmill set to 4mph and 4deg incline. My heart rate gets up to 150 bpm by the end.

Used to run but was always getting sore knees. Now I walk and it’s very consistent.