Why does the arrow option in plot() not work when plotting with 3 axes?

For some reason, the arrow=true argument doesn’t seem to have any effect once I give plot a three-dimensional line. Is this a bug, or intended behaviour? Is there a way to get arrow heads in 3D, without having to resort to the (imo) more convoluted arrow or quiver functions?

plot([0, 1], [0, 1], arrow=true, linewidth=2, label="")

2darrow

plot([0, 1], [0, 1], [0, 1], arrow=true, linewidth=2, label="")

3darrow