Edit: NSAIDs are bad if you are bleeding (or are about to be bleeding like before surgery), and they can cause stomach ulcers.
Opioids : Nuke :: NSAID : Knife
Looking at it, it seems the dose made the difference entirely. That said for minor pain it's often enough.
Of course 99.9% of American adults are desensitized to caffeine, so are unable to utilize its medicinal effects.
"A mild and transitory vasoconstrictor effect exists, which depends mainly on the caffeine concentration in the VSMC. However, the main and predominant effect of caffeine on the vascular wall is vasodilating, acting equally on the VSMC directly or indirectly and also on the endothelial structure."
The paper also says that withdrawal headaches are caused by vasodilation so I was wrong about that.
"When you abruptly stop the consumption of caffeine in a habitual consumer, there is a greater number of available adenosine receptors, which potentiates the vasodilation produced by adenosine, causing the symptoms"
But your comment is spot on for many, caffeine withdrawal is also a major headache trigger.
https://www.sciencedaily.com/releases/2005/01/050111123706.h...
So each drug has its place. There is no "one size fits all"
I think it's good there are multiple options and people can just take what works for them.