For one thing, degrees may have an arbitrary basis, but they are absolute and that has to count for something. In fact, it counts for a lot. I can always tell you how many degrees are in a circle. Period. If someone is standing on one side of an object and I need them to go to another side, I can just tell them to go 90 degrees around it — I don’t need to know how far away they are to calculate the radians, and then convert that into distance, and then figure out how they’re going to measure the distance they’ve traveled.

Another issue is that radians only measure relative distance. Very few people would answer in radians if you asked them how far around a track they ran. They would answer in meters or the like. I can’t speak for all humans, but we Americans like to think in terms of absolutes.

That is not at all to say that radians are useless. Degrees are useful for arcs and direction; radians are useful for mechanics and rotation. So radians are excellent for scientific purposes, such as dealing with gears and pulleys and the like.

But radians require more information and precise measurement with no specific frame of reference, and since degrees are absolute it’s much easier to visualize them. The problem with radians is that most of the time we don’t know (or care) about the radius of a circle, and even if we did, a relative unit of measurement is not particularly handy.

So I do appreciate the effort to make this concept more approachable, but I think some of the confusion in the comments stems from the fact that radians simply don’t reflect the way we deal with our everyday lives. Perhaps this article strives a little too much to lean in that direction.