The climate spiral can be misleading though, because it's natural for a viewer to interpret the change in terms of area.
Then, the increase from 1.5° to 2° looks much, much larger than the increase from 0° to 0.5°.
So it's misleading in terms of making recent warming seem even worse than it is. Now, of course, you might argue that is justified in spirit because the negative consequences from warming grow faster than linear... but that doesn't make it any less misleading in terms of the temperature change it is communicating.
They often are not, because they highly distort shape and size. Values that are smaller than the mean occupy much less space (area-wise) and seem less significant than they really are, while values that are larger than the mean occupy much more space (area-wise) and seem more significant than they really are.
Then, the increase from 1.5° to 2° looks much, much larger than the increase from 0° to 0.5°.
So it's misleading in terms of making recent warming seem even worse than it is. Now, of course, you might argue that is justified in spirit because the negative consequences from warming grow faster than linear... but that doesn't make it any less misleading in terms of the temperature change it is communicating.